Once Buddah post, you'll have a limited amount of banter time before Rilla prepares and post the fights. Once you have your assigned fights, you will proceed to the teleportors located in the lobby. Your fights will be located on separate threads, obviously to make it easier on you and the judges and in this case, mentors, to keep track of. The fight post will have a somewhat detailed description of where you will be fighting.  You will take it from there. 

The initial post in the fight, you are not allowed to make any kind of attacks. Rilla will decides who post first. So, first 2 post on the thread should contain no attacks.  The 3rd post, which should be written by whoever went first, should contain the first attack. However, that isn't required. But, it's open season at that point.

Remember this, because it is used in any arena fight you'll have here. Except for who goes first. If you participate in a fight outside of the tournament, it will be up to you and your opponent to decide. I think there usually is a general rule of challenger making the first post. Though, it's still up to you both. But in a tournament setting, the host will generally always make that decision, often through just some kind of randomized process.