I've put in quite a bit of details pertaining to Pokemon Contests.

There will be different entry requirements for each rank, usually just meaning it requires more and more Pokemon to enter each succeeding rank.

All contests except Master will feature two stages, Appeal Stage and Battle Stage, which is similar to how they are in the anime. A prelims to appeal to the audience, and then a finale where coordinators try and outshine one another to a table of judges in front of a crowd.

However, the Master Rank will feature the Performance Stage.

With up to 6 Pokemon, perform at the Brittania Stadium in front of a massive crowd. You can perform anything, from a magic show, to a concert, it's really up to you.