Instructions
Look up and write down the GameShark cheat codes you wish to use. You can find cheat codes on the official GameShark website, or from cheat code lists on sites such as Super Cheats or GameFAQs. For example, the code "32C96211F488" disables random encounters in "Pokemon Emerald."
Start Visual Boy Advance, and load your "Pokemon Emerald" game.
Select the "Cheats" menu, and choose "Cheat List."
Click "Add Cheat," and enter your cheat code. Once enabled, the cheat code will run until you delete it from the list.