How to insert sound files?

Hey there, I’m afraid I have an issue with inserting sound files correctly…
I have a sound file prepared that is supposed to play during the whole video.
It seems like I have to insert it in every scene again and again, but this way they all overlap in the end.
The guide doesn’t really help at all, it only says ‘‘If the sound extends into multiple scenes, it will continue to play.’’ Maybe I’m just too stupid, but the way I understand this sencence it doesn’t work.
I’d be very pleased to receive a helpful answer^u^

This isn’t really an answer to your question, but you might want to consider adding your audio post-rendering using something like Mixcraft 6 or GarageBand. TBS’s audio capabilities are pretty rudimentary compared with either of these tools.