Your adventure begins in Littleroot Town! After moving into your new home, head next door to meet your rival, May/Brendan. Then, venture north onto Route 101. You'll hear Professor Birch calling for help, being chased by a wild Poochyena. He'll ask you to choose a Pokémon from his bag: Treecko, Torchic, or Mudkip. This will be your starter Pokémon. After rescuing him, return to his lab for your very own Pokédex and some Poké Balls. Your journey truly begins now!
Head north through Route 101, then Route 103 (where you'll have your first rival battle), and finally Route 102 to reach Oldale Town. Stock up on Potions if needed. Continue west through Route 102, battling trainers and catching new Pokémon, until you reach Petalburg City. Here, your father, Norman, is the Gym Leader. He'll introduce you to Wally and ask you to help him catch a Ralts. After this, he advises you to challenge Gyms. Head west onto Route 104, through Petalburg Woods, and then north to Rustboro City, home of the first Gym.