The button cluster on the left side contains:
Play in the center.
Previous to the left.
Next on the right side.
Stop on the bottom.
Eject on the top.
The center window displays information about the file being played.
The icons along the bottom allow you to setup Random play, Loop, Tracklist, and Mute.
The three buttons on the top and center right are:
Volume control – place your cursor on the white dot, hold down the right mouse key and drag it to the desired level.
The - button lets you minimize KsCD.
The X icon closes the application.