The PlayStation 2 controller is used during gameplay and cheat code entry [ view PS2 Cheats], on the following page the image below will be referenced to describe how PS2 cheats are entered.
Many times abbreviations will be used in cheat codes, an example of this is saying press L1, meaning press the Left #1 Shoulder Button. (#1 on the image)
For details on all of the buttons go to the next page. You can bookmark or print the following page for easy reference until you are familiar with the controller and the button descriptions.