Your first destination in the land of Kitakami is Mossui Town, where you meet Carmine and Kieran.
Before Carmine will let you into Mossui Town, you have to defeat her in battle. The levels of her pokémon, and the prize money, will depend on how many gym badges you have. If you completed the main story of Pokémon Scarlet or Violet already, she has a level 60 Poochyena, a level 60 Vulpix, and a level 60 Poltchageist. You get 3360 Pokédollars for winning.
Go to the Community Center
After the battle, there will be a cutscene, and the town Caretaker asks you to go to the Community Center. When you approach it, there will be another cutscene.
You can optionally talk to the person behind the desk to change your settings for the appearance of the menu depending on your location.
When you're ready to proceed, go up to the double doors that lead to the bedrooms, and say Yes. There will be a cutscene. You will get the Roto-Stick, which adds new features to your camera. You also learn the Eureka emote. The emote is in the list of Selfie Mode emotes when using the camera.
Afterward, talk to Carmine and Kieran, and there will be another cutscene. When Carmine asks if you want to pair up with one of them, say Yes. Then when she asks if you will battle Kieran, say Yes, and the battle will start.
The levels of Kieran's pokémon, and the prize money, will depend on how many gym badges you have. If you completed the main story of Pokémon Scarlet or Violet already, Kieran has a level 59 Sentret and a level 60 Yanma. You get 2640 Pokédollars for winning.
Explore Mossui Town
Afterward, the Caretaker will mark the locations of the three signs on your map. You can buy supplies at Peachy's in Mossui Town any time. Kieran says to visit the signboard to the west first, but before you go, you can explore the town to find some items, such as TM128 Amnesia in the truck behind Peachy's, TM173 Charge on the roof of the Community Center, and TM036 Rock Tomb on a hill northwest of the Community Center. Beneath the eastern bridge of the town, you can find TM177 Spite.
After you have healed your pokémon several times, the Pokémon Center lady will give you the Upside-Down Double Peace pose. Press up on the directional pad to find it in the Emotes list. She will eventually teach you the Poké Ball emote, which you can find when you use your camera in Selfie Mode. The Poké Ball that you hold up will be the one that your lead pokémon is in.
When you go west, you will see a photographer taking pictures. This is Perrin, who will take your photo, and will say to come back after you have registered 150 pokémon in the Kitakami Pokédex.
When you are ready, go west and you will arrive in the Apple Hills.