Galarian Star Tournament
The Galarian Star Tournament is unlocked at the end of The Crown Tundra after completing all three Legendary Clues and returning the Fourth Legendary Clue to Peony in Max Lair. As soon as you leave the Max Lair, you will receive a phone call from former champion Leon, who will ask you to come to Wyndon Stadium for something.
Fly to Wyndon Stadium and head straight to the stadium itself, where you'll be introduced to the Galarian Star Tournament with several of Galar's top coaches, including gym leaders and rivals. This tournament is team based, with battles being 2v2.
To start with, you need to choose a partner for your first tournament participation, as you are very limited the first time. Later you will have a choice of other partners, but for starters you can only choose between Hop and Marnie. Speak of your choice in the lobby, then go up to the entrance counter to begin the tournament.
In the Galarian Star Tournament, your partner and all opponents will have three Pokémon with them, although you still have all six at your disposal in battle. The battle will play out like a regular team battle, where you and your partner alternate pick attacks and try to defeat both of your opponents. These look like gym battles throughout the game as Dynamax plays an important role and you are always going to see one of your Dynamax opponents before the battle is over.
The tournament starts with 16 coaches in total, meaning there are eight teams in total. At the start, two of these trainers are listed as ???, which you will eventually discover. To win the whole tournament, you will need to win three consecutive battles, which you shouldn't have too much trouble getting, especially with the number of Pokémon perks you have.
Each trainer will have Pokémon in the lower to mid 70's range, so plan your squad accordingly. For those who have leveled their entire team, this might be the time to try out other Pokemon to make it a bit more of a challenge, although you can also browse them easily if you want to too.
After beating the Galarian Star Tournament for the first time, it will open up and be something you can participate in as much as you want. You can choose other partners this time and continue playing as you wish. Completing this tournament for the first time will also unlock the expansion's full final credits with a group of Pokémon swinging in front of a sold-out stadium. As soon as you turn the game back on, you will be at the stadium entrance counter and will be rewarded with a sports uniform, 1 Pokémon dollars and a nugget.