For one time sounds:

sound sound_name

 

For looping sound (usually for music):

music sound_name

 

To turn off the sound or music:

sound off

music off

 

To change the volume of the sound or music:

volume sound x T

volume music x T

x is the volume level from 0 to 100
is time in milliseconds (1000 milliseconds is 1 second)

Example:

music music_fashionedge
volume music 0 2000

(with the above commands, the music volume will go to level 0 in 2 seconds making the music seem like it's fading out)

Always remember that if you change the volume level to 0, you have to turn it back up later otherwise you will not be able to hear the music/sound.