Selecting a track to play
You do not necessarily need to play the first track on the list.
To play another track, first select it with your mouse, then click on the 'Play' button.
Music Player will now play the selected track (and all tracks that come after it in the list).
Pressing 'Play' while another track is playing
If another track is already playing while you press the 'Play' button, the active track will be interrupted before the selected track (or first track) will perform.