There is a ‘Do not enter’ light above the door to the dark room, that you flick on when developing, so that no one comes in and lets light in. Or there may be a 2-door airlock/lightlock.

There are big tongs with rubber ends, to move the photo-paper from one chemical bath to the next while developing.

I forget how to make white-borders around photos, maybe tape each of the 4 sides.