After Professor Kukui takes you through Route 1, you go to Iki town to find an island kahuna.
Find the Kahuna
Professor Kukui asks you to find the island kahuna so you can get your starter pokémon.
Go north and go up the stairs. You will see the blonde girl from the intro sequence. Apparently, the hidden creature in her bag wants to go to the ruins.
If you go to the left and talk to the guy in front of the building, he tells you that Kahuna Hala is not there right now.
Next, go up the path where the blonde girl went.
As you go up the trail, you will see the blonde girl again. During a cut scene, a mysterious pokémon will float out of her bag onto the bridge, only to be attacked by three Spearows.
When you go up to the girl, she asks you to save her pokémon. Go across the bridge. Sometimes you will stumble, but keep going up. When you reach the pokémon, there will be a cut scene.
Back to Iki Town
The girl will give you the Sparkling Stone. Afterward, go south toward the girl to go back to town with her. Professor Kukui introduces her as his assistant, Lillie.
Kahuna Hala returns. After a cut scene, you can choose your starter: the grass-type Rowlet, the fire-type Litten, or the water-type Popplio.
After you choose your pokémon, there will be a cut scene, and Professor Kukui will give you a Pokédex and a Trainer Passport.
If you open your menu, there are new options available. You can look at your new pokémon. You can take a look at your Trainer Passport, where you can customize your trainer portrait photo.
You can also look at the pokédex, which only has your starter pokémon in it so far.
There is also a new mini-game, Pokémon Refresh, which is similar to Pokémon Amie from Pokémon X and Y. Once a day, you can get Poké Beans in the café of any Pokémon Center and feed them to your pokémon in Pokémon Refresh. There will be other ways to get Poké Beans as you progress in the game. Also in Pokémon Refresh, you can groom your pokémon to clean them if they get dirty, and you can also heal status conditions like poisoning or paralysis. You can play Pokémon Refresh with any of the pokémon that you are carrying.
Go south toward Route 1. Hau will arrive and challenge you to a pokémon battle. If you are ready to battle, talk to Hau and agree to battle. Hau has chosen the starter who is weak to the one that you chose, so use your pokémon's elemental attack if available. It will be super-effective against Hau's pokémon.
Kahuna Hala will ask to see your Sparkling Stone. He will give it back to you the next day. He invites you to the festival tomorrow.
You will automatically go back home and introduce your starter pokémon to Mom. The next day, you will go to the Festival.