Once you've added a sound to your animation, you have a few simple sound editing options at your disposal:

Modify the volume level of your sound: To do that, first select the sound in the Timeline (its background turns blue when selected). You will see a Volume slider under Object Properties on the right side of the Editor. Use this slider to select the volume level you want:

Split your sound:
First position the Playhead (the vertical red line) where you want to split the sound. Next, right-click the sound layer in the Timeline. Select “Split Sound” in the right-click menu and your sound will be split over two layers:

Add a Fade In or Fade Out effect to your sound:
To do that, first select your sound and click "Add Effect". You can adjust the length of the Fade effect by dragging the small border bullets to the left or the right:

Did this answer your question?