Instructions
Insert the game you want to play into the empty slot in the back of your GameShark device. Don't force it. The label of the video game should be facing toward you as you insert the cartridge.
Insert your GameShark into the video game cartridge slot on your Game Boy Advance. GameShark plugs in the same way as a standard video game.
Set the On/Off switch on your GameShark to "On" then boot up your Game Boy Advance. The GameShark menu will load on your GBA and automatically detect the game you inserted. If the game you are using isn't in the GameShark database, it will take you to the "Game Name List" screen where you can enter in the name of the game you are using by selecting the "Add New Game" option.
Press the "A" button to activate all cheats for the game you selected if the cheat codes are already pre-loaded. You can alternatively press "Right" on the D-Pad to bring up the "Cheat Descriptions" list and choose which codes you want to activate individually by pressing the "A" button. If cheats are not pre-loaded, select the "Add New Cheat" option after you have selected the game you want to play and use the on-screen keyboard to manually enter in the cheat description and code.
Press the "Start" button on your GBA after you selected the cheats you want to use to begin playing. GameShark may sometimes cause glitches during game-play if you have a large number of cheats activated. If you experience any problems, try restarting your Game Boy and activate fewer cheats the next time you load your game.