If you mean by no$gba, Go to Utility -> Cheats -> click 'Add New' button -> insert your cheats on the given box -> click 'Ok', -> enable the cheats -> and play it.
Very simple! Press F2! Then, press Add New button, insert the codes you found it from somewhere. Next, click Action Replay OR Codebreaker depend of this type and click OK. Make sure the are no ? sign show out. Enable the codes by check it and click OK. Enjoy the games!