1. The first thing you'll see when you start it up is a japanese keyboard. Type in any random gibberish in Japanese, and there'll be a large rectangular button around the bottom right of the screen. That's confirm. Click it. Now you'll come to the main menu where you can choose from DS game, Pictochat, DS download play and GBA game.
2. Right at the bottom of the screen and in the middle, is a tiny icon of a ds. Tap that.