Pokémon Emerald walkthrough/Route 101

Route 101
As you enter the route, you'll see Prof. Birch running around in circles, being chased by a Zigzagoon. The Zigzagoon corners him, and then you have to go and save him. He'll ask you to take a Pokémon from his bag. Press A against the bag, and you'll have to select your starter.

As soon as you pick your starter, a battle with the Zigzagoon will commence.

After the battle, Birch will take you back to his lab, and will allow you to keep the Pokemon you used earlier. Give it a nickname if you wish (ten characters maximum). He'll force you to go visit Brendan/May on Route 103, so he/she can teach you what it means to be a Pokemon Trainer.

In order to get to Route 103, you need to take Route 101 to Oldale Town. With ledges blocking the way, you must go through the tall grass to keep moving north. Pokémon can be battled, but not captured, seeing as you don't have any Poké Balls yet. It is possible to train if you wish to raise your level to at least 7 or 8 to make it easier to face Brendan/May.

Head over to Oldale Town.