If I were you I wouldn’t go to open gym. Unless there are at least 10 court’s minimum, I would recommend just playing outside or somewhere else. If that’s the only court available to you, then that’s a different story. In my experience, Open gyms are terrible. I’ve never had one at school but from rec leagues and stuff, I know you need a big gang or group of friends to actually get to play. Depending on which grade your in, you most likely won’t get a chance to play if your school is like most schools (2-3 courts) if your a senior or have a lot of clout and are really popular, then they MIGHT let you play, but most likely not. If it is a open gym you probably don’t have to try out to the team but your case might be different. And definitely don’t try to hop on some random kids courts. No offense, but I can guarantee you that they are 10 times bigger and better than you. If you think you are better, prove it to them. Otherwise stick to outdoor courts