the way a trainer works (memory hack) is by changing the value of an address. if you change the address then load the game, the game will reset the value to what it wants.
you must run the game first (get in game and play) and then press the button.
if it dont work, the cheat is probably for a different version of the game and you cant get it to work so dont ask lol.
hopefully i wont have to hold your hand to start the game