How can you connect a swift file with an SKscene?

I looked through all posts, WWDC talks and youtube videos, but I still can't figure out how to have multiple SKscenes for different levels and connecting them with swift files in a Game using Spritekit. I want to have a main level board and I managed to open a new scene if you press a SKSpriteNode, but how can I implement game logic to this specific SKScene? Apologies in advance if it is a silly question, I've been spending ages on it.