Instructions
Insert the GameShark device into the empty cartridge slot on your Game Boy Advance.
Place the "Pokemon LeafGreen" cartridge into the empty slot on the GameShark device.
Turn on the Game Boy Advance. It will automatically load the GameShark menu.
Select "Pokemon LeafGreen" from the list of games presented by the GameShark device.
Select the cheat codes you wish to enable, and then hit the Start button to begin the game.