A little sound help Please

[Driftwood]

Am trying my luck at adding some sounds, music, etc. Two things that I would like to work on is adding wav file for when my sub dives and being able to add a wav file after a certain amount of time has elapsed on custom made scenario (WF time for those SW's out there). I've got sound edit and a sound editor (Nero 7) but haven't a clue where to place these sounds once I make them. Thanks in advance for any help you can provide.