How would I go about making multiple floors with stairs connecting them? I'm sure there's a simple solution but I can't really think of one

Perhaps making exits going “out” for up, and “in” for down?

You can make exits going "up" and "down". They just work.

If you want to arrange all the rooms on one floor together in the editor, you can make a room for each floor and put other rooms inside it. The game doesn't care about this, it would be just to help you organise them.

If you want to do something more complex, maybe you could explain in more detail what you want them to do.