diff --git a/musicdb-client/src/gui.rs b/musicdb-client/src/gui.rs
index d275768..c4d940c 100755
--- a/musicdb-client/src/gui.rs
+++ b/musicdb-client/src/gui.rs
@@ -204,27 +204,36 @@ pub trait GuiElemTrait {
 }
 
 #[derive(Debug, Clone)]
+/// The config for any gui element.
 pub struct GuiElemCfg {
     pub enabled: bool,
     /// if true, indicates that something (text size, screen size, ...) has changed
     /// and you should probably relayout and redraw from scratch.
     pub redraw: bool,
+    /// Position relative to the parent where this element should be drawn.
+    /// ((0, 0), (1, 1)) is the default and fills all available space.
+    /// ((0, 0.5), (0.5, 1)) fills the bottom left quarter.
     pub pos: Rectangle,
     /// the pixel position after the last call to draw().
     /// in draw, use info.pos instead, as pixel_pos is only updated *after* draw().
     /// this can act like a "previous pos" field within draw.
     pub pixel_pos: Rectangle,
+    /// which mouse buttons were pressed down while the mouse was on this element and haven't been released since? (Left/Middle/Right)
     pub mouse_down: (bool, bool, bool),
+    /// Set this to true to receive mouse click events when the mouse is within this element's bounds
     pub mouse_events: bool,
+    /// Set this to true to receive scroll events when the mouse is within this element's bounds
     pub scroll_events: bool,
     /// allows elements to watch all keyboard events, regardless of keyboard focus.
     pub keyboard_events_watch: bool,
     /// indicates that this element can have the keyboard focus
     pub keyboard_events_focus: bool,
     /// index of the child that has keyboard focus. if usize::MAX, `self` has focus.
-    /// will automatically be changed when Tab is pressed. [TODO]
+    /// will automatically be changed when Tab is pressed (Tab skips elements with keyboard_events_focus == false)
     pub keyboard_focus_index: usize,
+    /// if this is true and ResetKeyboardFocus is returned, this element may get the keyboard focus (guaranteed if no other element has this set to true)
     pub request_keyboard_focus: bool,
+    /// if this is true, things can be dragged into this element via drag-n-drop
     pub drag_target: bool,
 }
 impl GuiElemCfg {
@@ -281,9 +290,10 @@ pub enum GuiAction {
     OpenMain,
     SetIdle(bool),
     OpenSettings(bool),
+    /// Build the GuiAction(s) later, when we have access to the Database (can turn an AlbumId into a QueueContent::Folder, etc)
     Build(Box<dyn FnOnce(&mut Database) -> Vec<Self>>),
     SendToServer(Command),
-    /// unfocuses all gui elements, then assigns keyboard focus to one with config().request_keyboard_focus == true.
+    /// unfocuses all gui elements, then assigns keyboard focus to one with config().request_keyboard_focus == true if there is one.
     ResetKeyboardFocus,
     SetDragging(
         Option<(
@@ -292,6 +302,7 @@ pub enum GuiAction {
         )>,
     ),
     SetLineHeight(f32),
+    /// Run a custom closure with mutable access to the Gui struct
     Do(Box<dyn FnMut(&mut Gui)>),
     Exit,
 }
@@ -301,6 +312,9 @@ pub enum Dragging {
     Song(SongId),
     Queue(Queue),
 }
+
+/// GuiElems have access to this within draw.
+/// Except for `actions`, they should not change any of these values - GuiElem::draw will handle everything automatically.
 pub struct DrawInfo<'a> {
     pub actions: Vec<GuiAction>,
     pub pos: Rectangle,
@@ -316,6 +330,7 @@ pub struct DrawInfo<'a> {
     pub line_height: f32,
 }
 
+/// Generic wrapper over anything that implements GuiElemTrait
 pub struct GuiElem {
     pub inner: Box<dyn GuiElemTrait>,
 }
diff --git a/musicdb-client/src/gui_base.rs b/musicdb-client/src/gui_base.rs
index 7933c53..0511729 100755
--- a/musicdb-client/src/gui_base.rs
+++ b/musicdb-client/src/gui_base.rs
@@ -7,6 +7,13 @@ use crate::{
     gui_text::Label,
 };
 
+/*
+
+Some basic structs to use everywhere.
+Mostly containers for other GuiElems.
+
+*/
+
 /// A simple container for zero, one, or multiple child GuiElems. Can optionally fill the background with a color.
 #[derive(Clone)]
 pub struct Panel {
diff --git a/musicdb-client/src/gui_library.rs b/musicdb-client/src/gui_library.rs
index 5db9ea2..0595d0e 100755
--- a/musicdb-client/src/gui_library.rs
+++ b/musicdb-client/src/gui_library.rs
@@ -14,6 +14,13 @@ use crate::{
     gui_wrappers::WithFocusHotkey,
 };
 
+/*
+
+This is responsible for showing the library,
+with Regex search and drag-n-drop.
+
+*/
+
 #[derive(Clone)]
 pub struct LibraryBrowser {
     config: GuiElemCfg,
diff --git a/musicdb-client/src/gui_playback.rs b/musicdb-client/src/gui_playback.rs
index 695cc69..2729937 100755
--- a/musicdb-client/src/gui_playback.rs
+++ b/musicdb-client/src/gui_playback.rs
@@ -9,6 +9,13 @@ use crate::{
     gui_text::Label,
 };
 
+/*
+
+Components for the StatusBar.
+This file could probably have a better name.
+
+*/
+
 #[derive(Clone)]
 pub struct CurrentSong {
     config: GuiElemCfg,
diff --git a/musicdb-client/src/gui_queue.rs b/musicdb-client/src/gui_queue.rs
index 58fb76c..95b8be0 100755
--- a/musicdb-client/src/gui_queue.rs
+++ b/musicdb-client/src/gui_queue.rs
@@ -20,6 +20,15 @@ use crate::{
     gui_text::Label,
 };
 
+/*
+
+
+This is responsible for showing the current queue,
+with drag-n-drop only if the mouse leaves the element before it is released,
+because simple clicks have to be GoTo events.
+
+*/
+
 #[derive(Clone)]
 pub struct QueueViewer {
     config: GuiElemCfg,
diff --git a/musicdb-client/src/gui_screen.rs b/musicdb-client/src/gui_screen.rs
index 2a42e64..22fa15f 100755
--- a/musicdb-client/src/gui_screen.rs
+++ b/musicdb-client/src/gui_screen.rs
@@ -12,7 +12,15 @@ use crate::{
     gui_text::Label,
 };
 
-/// calculates f(p) (f(x) = 3x^2 - 2x^3)):
+/*
+
+The root gui element.
+Contains the Library, Queue, StatusBar, and sometimes Settings elements.
+Resizes these elements to show/hide the settings menu and to smoothly switch to/from idle mode.
+
+*/
+
+/// calculates f(p), where f(x) = 3x^2 - 2x^3, because
 /// f(0) = 0
 /// f(0.5) = 0.5
 /// f(1) = 1
@@ -36,9 +44,6 @@ pub struct GuiScreen {
     pub prev_mouse_pos: Vec2,
 }
 impl GuiScreen {
-    fn i_statusbar() -> usize {
-        0
-    }
     pub fn new(
         config: GuiElemCfg,
         line_height: f32,
diff --git a/musicdb-client/src/gui_text.rs b/musicdb-client/src/gui_text.rs
index 2cd6369..43fa92a 100755
--- a/musicdb-client/src/gui_text.rs
+++ b/musicdb-client/src/gui_text.rs
@@ -10,6 +10,13 @@ use speedy2d::{
 
 use crate::gui::{GuiAction, GuiElem, GuiElemCfg, GuiElemTrait};
 
+/*
+
+Some basic structs to use everywhere,
+except they are all text-related.
+
+*/
+
 #[derive(Clone)]
 pub struct Label {
     config: GuiElemCfg,
diff --git a/musicdb-lib/src/data/database.rs b/musicdb-lib/src/data/database.rs
index 3b63c76..384640b 100755
--- a/musicdb-lib/src/data/database.rs
+++ b/musicdb-lib/src/data/database.rs
@@ -18,7 +18,9 @@ use super::{
 };
 
 pub struct Database {
+    /// the path to the file used to save/load the data
     db_file: PathBuf,
+    /// the path to the directory containing the actual music and cover image files
     pub lib_directory: PathBuf,
     artists: HashMap<ArtistId, Artist>,
     albums: HashMap<AlbumId, Album>,
@@ -26,13 +28,18 @@ pub struct Database {
     covers: HashMap<CoverId, DatabaseLocation>,
     // TODO! make sure this works out for the server AND clients
     // cover_cache: HashMap<CoverId, Vec<u8>>,
+    // These will be used for autosave once that gets implemented
     db_data_file_change_first: Option<Instant>,
     db_data_file_change_last: Option<Instant>,
     pub queue: Queue,
+    /// if the database receives an update, it will inform all of its clients so they can stay in sync.
+    /// this is a list containing all the clients.
     pub update_endpoints: Vec<UpdateEndpoint>,
+    /// true if a song is/should be playing
     pub playing: bool,
     pub command_sender: Option<mpsc::Sender<Command>>,
 }
+// for custom server implementations, this enum should allow you to deal with updates from any context (writers such as tcp streams, sync/async mpsc senders, or via closure as a fallback)
 pub enum UpdateEndpoint {
     Bytes(Box<dyn Write + Sync + Send>),
     CmdChannel(mpsc::Sender<Arc<Command>>),
@@ -41,6 +48,7 @@ pub enum UpdateEndpoint {
 }
 
 impl Database {
+    /// TODO!
     fn panic(&self, msg: &str) -> ! {
         // custom panic handler
         // make a backup
@@ -50,6 +58,7 @@ impl Database {
     pub fn get_path(&self, location: &DatabaseLocation) -> PathBuf {
         self.lib_directory.join(&location.rel_path)
     }
+    // NOTE: just use `songs` directly? not sure yet...
     pub fn get_song(&self, song: &SongId) -> Option<&Song> {
         self.songs.get(song)
     }
@@ -72,6 +81,7 @@ impl Database {
         }
         id
     }
+    /// used internally
     pub fn add_song_new_nomagic(&mut self, mut song: Song) -> SongId {
         for key in 0.. {
             if !self.songs.contains_key(&key) {
@@ -89,6 +99,7 @@ impl Database {
         let id = self.add_artist_new_nomagic(artist);
         id
     }
+    /// used internally
     fn add_artist_new_nomagic(&mut self, mut artist: Artist) -> ArtistId {
         for key in 0.. {
             if !self.artists.contains_key(&key) {
@@ -110,6 +121,7 @@ impl Database {
         }
         id
     }
+    /// used internally
     fn add_album_new_nomagic(&mut self, mut album: Album) -> AlbumId {
         for key in 0.. {
             if !self.albums.contains_key(&key) {
diff --git a/musicdb-lib/src/data/mod.rs b/musicdb-lib/src/data/mod.rs
index 053af29..16451c8 100755
--- a/musicdb-lib/src/data/mod.rs
+++ b/musicdb-lib/src/data/mod.rs
@@ -17,11 +17,13 @@ pub type ArtistId = u64;
 pub type CoverId = u64;
 
 #[derive(Clone, Default, Debug)]
+/// general data for songs, albums and artists
 pub struct GeneralData {
     pub tags: Vec<String>,
 }
 
 #[derive(Clone, Debug)]
+/// the location of a file relative to the lib directory, often Artist/Album/Song.ext or similar
 pub struct DatabaseLocation {
     pub rel_path: PathBuf,
 }
diff --git a/musicdb-lib/src/server/mod.rs b/musicdb-lib/src/server/mod.rs
index 1afa904..c940098 100755
--- a/musicdb-lib/src/server/mod.rs
+++ b/musicdb-lib/src/server/mod.rs
@@ -81,6 +81,8 @@ pub fn run_server(
     sender_sender: Option<tokio::sync::mpsc::Sender<mpsc::Sender<Command>>>,
 ) {
     let mut player = Player::new().unwrap();
+    // commands sent to this will be handeled later in this function in an infinite loop.
+    // these commands are sent to the database asap.
     let (command_sender, command_receiver) = mpsc::channel();
     if let Some(s) = sender_sender {
         s.blocking_send(command_sender.clone()).unwrap();
@@ -91,6 +93,7 @@ pub fn run_server(
             Ok(v) => {
                 let command_sender = command_sender.clone();
                 let db = Arc::clone(&database);
+                // each connection gets its own thread, but they will be idle most of the time (waiting for data on the tcp stream)
                 thread::spawn(move || loop {
                     if let Ok((mut connection, con_addr)) = v.accept() {
                         eprintln!("[info] TCP connection accepted from {con_addr}.");
@@ -100,10 +103,15 @@ pub fn run_server(
                             // sync database
                             let mut db = db.lock().unwrap();
                             db.init_connection(&mut connection)?;
+                            // keep the client in sync:
+                            // the db will send all updates to the client once it is added to update_endpoints
                             db.update_endpoints.push(UpdateEndpoint::Bytes(Box::new(
+                                // try_clone is used here to split a TcpStream into Writer and Reader
                                 connection.try_clone().unwrap(),
                             )));
+                            // drop the mutex lock
                             drop(db);
+                            // read updates from the tcp stream and send them to the database, exit on EOF or Err
                             loop {
                                 if let Ok(command) = Command::from_bytes(&mut connection) {
                                     command_sender.send(command).unwrap();
@@ -121,6 +129,8 @@ pub fn run_server(
             }
         }
     }
+    // for now, update the player 10 times a second so it can detect when a song has finished and start a new one.
+    // TODO: player should send a NextSong update to the mpsc::Sender to wake up this thread
     let dur = Duration::from_secs_f32(0.1);
     loop {
         player.update(&mut database.lock().unwrap());
diff --git a/musicdb-server/src/main.rs b/musicdb-server/src/main.rs
index de3dc0f..6aa0331 100755
--- a/musicdb-server/src/main.rs
+++ b/musicdb-server/src/main.rs
@@ -25,6 +25,7 @@ use musicdb_lib::data::database::Database;
 
 #[tokio::main]
 async fn main() {
+    // parse args
     let mut args = std::env::args().skip(1);
     let mut tcp_addr = None;
     let mut web_addr = None;
@@ -148,20 +149,7 @@ this help was shown because no arguments were provided."
         );
         exit(1);
     };
-    // database.add_song_new(Song::new(
-    //     "Amaranthe/Manifest/02 Make It Better.mp3".into(),
-    //     "Make It Better".to_owned(),
-    //     None,
-    //     None,
-    //     vec![],
-    //     None,
-    // ));
-    // let mut player = Player::new();
-    // eprintln!("[info] database.songs: {:?}", database.songs());
-    // database.save_database(Some("/tmp/dbfile".into())).unwrap();
-    // eprintln!("{}", database.get_song(&0).unwrap());
-    // database.queue.add_to_end(QueueContent::Song(1).into());
-    // player.update_and_restart_playing_song(&database);
+    // database can be shared by multiple threads using Arc<Mutex<_>>
     let database = Arc::new(Mutex::new(database));
     if tcp_addr.is_some() || web_addr.is_some() {
         if let Some(addr) = web_addr {
@@ -177,8 +165,4 @@ this help was shown because no arguments were provided."
     } else {
         eprintln!("nothing to do, not starting the server.");
     }
-    // std::io::stdin().read_line(&mut String::new()).unwrap();
-    // dbg!(Update::from_bytes(&mut BufReader::new(
-    //     TcpStream::connect("127.0.0.1:26314".parse::<SocketAddr>().unwrap()).unwrap()
-    // )));
 }