Playing and stoping music

I have read the tutorials about creating a sound bar and how to play sounds unsing actionscripts, im quite confused.

I know how to play the sound using this:

on (release) {
kirupaSound = new Sound(this);
kirupaSound.start(0, 99);

But how to stop the sound? And how to play the next track, to pause them…
Pls help!

Using this
I have no idea of how to merge the two sound and sound1 files. Need help too!