I have to make a culture box for a school project and I don't know what to do. What goes in this box?

What culture have you chosen to portray? Once you've decided, you should do quite a bit of research about it and THEN you'll be ready to decide what to do. I'd say you could take a decent size cardboard box, cut off the top flaps, turn it on its side, and make a type of diorama. Instead of setting up a scene from a book or whatever, though, you'd be including items that set that particular culture apart from others.