Welcome to our community, Rich
After you import from PowerPoint, nothing is actually
editable in Captivate. You may certainly add audio, but that will
be on the tricksy side to get it synced to the animation. Also,
audio doesn't survive the trip from PowerPoint to Captivate.
Hate to be the bearer of bad news, but you are probably
better off re-creating in Captivate if that's your goal.
Cheers... Rick