Ok so im making a music widget and it all works fine apart from that when i press a button to change the music that is playing it just goes on top of the already playing music so basically i want the music playing to be muted when i press a button and to change to another track.
You just have to stop the other music… 
:C im being serious how do i do it.
It really depends on how you played the sound, but just drag a pin from the sound reference and look for stop. That should do it.