Tutorials » 
Adding Sound
Adding Sound to your Movie
Now that you've imported your sound you can now add it to your movie.
Think of a layer as a sound channel. You can have a many as you want
and they'll combine when you play the movie. Choose Insert> Layer to
create a layer for your sound. Click on the frame you want the sound
to start and insert a keyframe. Choose Modify> Frame and select the
sound tab in the Frame Properties dialog box. Now choose the sound
from the drop-down box.
Advanced: Many designers choose to place their background loops/sounds on a separate .swf file which is then loaded into their main timeline when it starts up. This allow them to stop and start music at will. Short sound fx however are best left in your main movie for ease of control.
