Instructions
Insert your Gameshark GBA device into the game slot on the top of your Game Boy Advance.
Insert your copy of "Pokemon LeafGreen" into the game slot on the Gameshark GBA device. Make sure the Gameshark device's power switch is in the On position.
Turn on your Game Boy Advance. Your GBA device will detect your game and immediately bring up the game's cheat list.
Select the cheats you wish to activate for "Pokemon LeafGreen" with the A button on your Game Boy Advance. Press the Start button when you are ready to begin playing with the cheats activated.