hey,

if u add it in maya it needs to be in .wave (cd format)

then in maya fo file and import chose file type as sound/audio and chose the track

on the timeline right click co to sound and chose the bottom option, u should see the wave form of the wound in the time line an there its done (make sure playback under preferences it set to realtime otherwise u wount hear it)
this is the way to do it if u are animating so u need to get the timing right

but if u wanna add sound and not make it to time ie sound track do this is a program like premiere arfter it has been rendered

hope this helps