Instructions
Turn on the Nintendo DSi XL and select the "System Settings" icon on the main menu.
Select "Internet." Select "Connection Settings." Select the "None" button next to Connection 1. Select "Search for an Access Point."
Select the name of your wireless network. If prompted, use the on-screen keyboard to enter the network's password. Select "OK." Select "Save Settings."
Select "Yes" to perform a connection test. If the test is successful, the Nintendo DSi XL will be connected to that network. If the test is unsuccessful, the problem and most likely solution will be displayed on-screen.