[player] [equalizer] [playlist] [credits]
Overall
There are 3 windows: the player, the equalizer and the playlist. Right-click anywhere to see a shortcut menu. Hover around to see funny cursors:
drag the bottom right corner of the Playlist window to resize it.
drag the title bar of a window to move it around
slide the slider. do it. you know you want to.
On the top of each window is a title bar, click the collapse button 
or double click the bar to collapse the window.
Player window [^top]
Far left bar: the only 2 buttons that matter are the 1st button (O) for option and the 4th button (D) that toggles doublesize.
To the right: a visualizer, track info and 2 small slides 
, 1st slide for volume and the 2nd for balance (left-right).
Some funky buttons:
toggle equalizer window
toggle playlist window
Under it is the track slide 
(draggable) and the control buttons
previous track
play
pause
stop
next track
open a file
toggle shuffle
toggle loop
if you click on the cool smiley, it takes you to Webamp's GitHub page.
Equalizer window [^top]
There is an array of vertical sliders here. I personally don't know what the hell this is about, but I'd recommend clicking around tweaking things and explore the 
, "Club" is my favorite preset so far.
If you're not happy with a preset, you can click on the smileys to set all sliders to one position.
Playlist window [^top]
This is the fun part. The playlist is self-explanatory enough, what's fun is you can scrap my playlist and listen to whatever you want while browsing my page.
[+file] is to add files: you can add a file 
or a directory (folder) 
from your computer. Adding file from an URL doesn't work anymore.
[-file] is to remove files. Option are to delete selected file, crop (delete all but selected file), clear all, and the misc function is not working.
[sel] is to select file(s), [misc] is to sort / export playlist.
The useless part: yet another frame with track info and control buttons (yes, those black icons are buttons). I think it's pretty overkill. Also, the [list] button doesn't work at all. The only functional thing about this part is the corner which you can drag and resize the window.
Credits [^top]
Webamp, an implementation of Winamp 2 in HTML5 and JavaScript by Jordan Eldredge, under the MIT license.
Skin: Mine Amp v1.0, an ode to Minesweeper, created by Amanda Gunther in 2001.
A human readable guide to embed Webamp written by Dokodemo on Neocities. More advanced stuff to be found at Webamp's API docs.