what do you do in them?
Trick Ladders are when you go up, do tricks off the trick list until you miss one(or however many are allowed) or complete the list, then somebody else goes and does it, or there could be more people on stage than just you, so you could just wait for them. If you have a certain competition that you are looking at then I could get more in-depth.
Usually you have to stay in a certain area, like a box marked with tape on the ground, you get one throw per trick, and get a test throw outside the box to test string tension and stuff, but the rules vary.