In this blog post I tried to explain audio objects: Audio Objects: Control them! - Captivate blog
However a pretty recent new command/statement 'Play audio' is available. You could use it for the On Enter event. And use it also for the button Success event, but be careful to do it using an advanced action (or shared action), not a simple action that would release the playhead. The advantage is that even if the original audio clip is still playing (from the On Enter event) when the button is clicked, that original audio clip will stop and the one (same) triggered by the button will start from the beginning. This is not the case if you pause/stop an audio object by hiding it.
Lilybiri