After you explore the artwork installations in Artazon, you challenge the Artazon Gym.
When you enter the Gym, Nemona will meet up with you. She will give you 3 Ethers.
Pass the Gym Test
Before you can battle Brassius, you have to pass the Gym Test by completing a game of Sunflora Hide-and-Seek. You need to look throughout Artazon and find up to 10 Sunflora, which look like sun-shaped flowers.
Go outside and go east to the Sunflora Lawn. Talk to the person standing in front of the gate to the Sunflora Lawn.
Turn around to face the west, and you will see three Sunflora nearby. Talk to each one so that they follow you.
Then go farther west and you will find a Sunflora next to a street lamp, but it will run away. When you catch up to it and talk to it, you will have to battle it. Its level is around 12-14. You can't catch it, so just focus on defeating it. Afterward, it will follow you.
There is a Sunflora on the east side of the windmill platform.
There is a Sunflora in the middle of the battle area on top of the windmill platform. It will battle you. Its level is around 12-14. As before, just focus on defeating it.
There is a Sunflora north of the swimming pool west of the Gym.
South of that, there is a Sunflora at the vending machines next to the pool.
West of that, there is a Sunflora in front of one of the food carts.
You can find another Sunflora if you go west to the paved walkway and go clockwise around it.
There may be Sunflora in other locations besides the ones listed above.
When you have up to 10 Sunflora, go back to the Sunflora Lawn and talk to the person there, and you will pass the Gym Test.
Grass Gym Leader Brassius, the Verdant Virtuoso
Go back into the Artazon Gym and talk to the person behind the counter. If you are ready to battle Brassius, say Yes.
Brassius has a level 16 Petilil, a level 16 Smoliv, and a level 17 Sudowoodo that he Terastallizes, with Tera Type Grass. You get 3060 Pokédollars for winning.
You will get a Gym Badge. Check the Gym Badge Effects page to see the level of Pokémon that will listen to you and be easier to catch, or open the Map App or Pokédex App and press X, then select Profile, then press A to see the effects of your current badges.
You also get a TM020 Trailblaze.
A new Gym Badge means new sandwich recipes. Be sure to stop by any Every Wich Way and talk to the person in front of the counter to learn some new recipes.