At the very start of the game, you’ll be greeted by Rowan, the Pokémon Professor of the Sinnoh region. He’ll offer to give you some basic instructions on the game’s controls or the adventure info if you ask him about it, otherwise you can just choose “No info needed” to proceed.
He’ll want you to touch the button in the middle of the Poké Ball on the bottom screen. Go ahead and do that, either with your finger or stylus, or whatever you have handy for interacting with the touch screen. A Munchlax will pop out from the Poké Ball!
He’ll talk for a bit longer about the world of Pokémon and will then ask whether you’re a boy or a girl. Go ahead and choose whichever player character you’d like to play as—it makes minimal impact on the gameplay itself, although whichever you don’t choose will be Professor Rowan’s assistant in the game instead. The boy’s canonical name is Lucas and the girl’s canonical name is Dawn, and these are the names that the assistant will use. For the sake of this walkthrough, it will be written from the perspective of the player choosing the boy, so the Professor’s assistant will be Dawn; if you choose to play as the girl, you’ll run into Lucas instead, although it’s very similar, except with a few different dialogue options.
You’ll also need to give the character a name. You have 7 characters to use to input your name, so go ahead and pick a fitting one. Remember that you can press the Select button to toggle between Uppercase and Lowercase, as well as “others” (symbols). In this game, Trainer names are properly capitalized, but Pokémon names are still in UPPERCASE, so keep that in mind while naming not just your character but also Pokémon later on (although it’s fine to give them proper capitalization).
Afterwards, you’ll have to give a name to your Rival character. His canonical name is Barry, although there are also a few other default options for you to choose, and you can also choose “New name!” to give him whichever name you’d like. For the sake of this walkthrough, he will be given the name “Barry”.
He’ll talk for a bit longer and will then send you off to start your adventure in the Pokémon world!