You, or your coach, should receive a Discord invite from the tournament director a few days before the tournament. Join this link as soon as possible so that the TD can assign you the proper role for the tournament. Once you join the server, rename yourself to your real name + school by typing a command like “/nick Michael Bentley (Washington)”. (Coaches: also add “coach” to the end of your username.) Read the code of conduct / honor pledge and agree to it.
If it’s been a while and you still aren’t listed as being part of a team role, @mention the tournament director to get you assigned. It’s especially important to do this if you join late (but please be on time!).
If your roster has recently changed, alert the tournament director about that.
Note that some tournaments may have multiple Discord servers. Pay attention to announcement mails from the TD and join all applicable servers if this is the case.