How do you type in chaets on Pokemon pearl?

If you have a DS card that has a lot of games in it, that's great. Theres a little box at the bottom of the touch screen and you press x. There will be a menu of cheats. You press x for the ones you want to use and then press a when you are done. When you start the game press x while the game is loading to activate the cheat(s) you have chosen.