Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
To not make it an useless post: Reminder that since this round is very likely to be still on during tier shifts, none of them are taken into account until round 2. As such you will have to challenge in USM OU, to account for the Drought ban in UU.