void OnStart() void OnEnter()

[The chaser]

It isn't necessary to use an "if". For example, a hub. You want that when you enter a map a quiet music sounds, like in the main game.

If you put in OnStart(), the music will only sound when you enter in that map, if you leave and enter another time the music won't sound.

If you use OnEnter(), the music will sound every single time you enter. If you leave and enter another time, the music will sound.

If you want to make more complicated things, go forward. Use "if"s if you need them.