Play an audio/sound at the beginning then have it gradually fade away.
wait(3) game.Workspace.Sound:Play()
That is all I have
What you can use is a for loop with the volume:
wait(3) game.Workspace.Sound:Play() wait(timeyouwantittoplaynormally) for i = 1,100 do wait(0.1) --Fades away taking 10 seconds game.Workspace.Sound.Volume = 1- (i/100) end