CWCheat

When you have CWCheat installed, launch a game. 
Wait for it to load completly, and hold the select button for about 5 seconds. 
A menu should pop up, go to the "Select Cheats" option and select whatever cheats you want on. 
Once done, go back to the main menu go to the option "Enable Cheats", and press the X button till it says "Enable Cheats [Y]". 
Now hold select again, to leave the menu. 
Enjoy your cheats.

https://gbatemp.net/threads/cwcheat-tutorial.291212/