After you start a new game, you begin Pokémon Ruby and Sapphire in Littleroot Town.
Start a New Game
When you start a new game, Professor Birch tells you about the world of pokémon. After that, choose whether you want your character to be a boy or a girl. Then you can choose one of the four default names for your character, or select NEW NAME and enter a custom name.
After you name your character and hear some more words from Professor Birch, you start the game in a truck. The truck stops, and the door opens. Walk to the right and go out. Your Mom will meet you and take you inside. After she is done talking, go upstairs to your room. Check on the clock on the wall and set it by pressing left or right on the control pad, then press A to set it. Afterward, your Mom will come up and talk to you, then she goes back downstairs. Check on the book on your desk. Then check on the computer. Be sure to chose Item Storage and then choose Withdraw Item, then choose the Potion. Then go downstairs again.
Downstairs, Mom calls you over to the TV, where Petalburg Gym is on the news. Apparently your Dad is at that gym. Your Mom then asks you to go next door and meet your Dad's friend, Professor Birch.
Go outside and go into the house to the left. The woman inside will introduce herself. She says to go upstairs and talk to her child, so do that. If your character is a girl, the character upstairs will be Brendan, and if your character is a boy, the character upstairs will be May. This is Professor Birch's child. After Brendan/May leave, go downstairs. The woman downstairs tells you that Professor Birch is probably at his lab now.
Leave the house and go into the house to the south. This is Professor Birch's lab. Talk to the scientist, who tells you that Professor Birch is doing field work.
Leave the lab and go north to the exit of town. When you walk past, the kid there says that he hears someone shouting from down the road. Go north and you see Professor Birch being chased by a Poochyena (or Zigzagoon in Emerald). He says to get a Pokéball from his bag. Check on the bag and you can choose a starter pokémon. You can choose either Torchic, Mudkip, or Treecko. Based on the types of pokémon that you will encounter soon, you will have the easiest time if you choose Treecko, it will be challenging if you choose Torchic, and the difficulty will be somewhere in the middle if you choose Mudkip. Each starter pokémon begins at level 5.
First Pokémon Battle
After you choose your starter pokémon, the pokémon battle will begin. You don't have any way to capture this pokémon, so just use Pound or Tackle or Scratch until Poochyena is defeated.
Get Ready for Your Journey
Afterward, you go to Professor Birch's lab. He lets you keep the starter pokémon that you chose when rescuing the Professor. He asks if you want to give it a nickname. Afterward, the Professor says that his child is in Route 103. Agree to meet up with Brendan/May. You can talk to your Mom to rest. Then go north to Route 101.