How do you get your RuneScape music to work

It should work immediately. First, try the obvious stuff - is your sound turned off? Does sound on other programs work?
If everything is working fine except RuneScape, go to the options menu (the wrench icon). Adjust your audio settings and make sure the sound is turned up.
It could be that the song you're on doesn't work. Go to the music icon and click on a new song (only the ones highlighted in green will play).
If that still doesn't work, I don't know how to help you.