Ghost Recon cheat help

[natjon]

I just started playing Ghost Recon. I want to enable the God mode cheat so that I can go around and not worry about being killed straight away....I will do this until I'm used to the game play and will then do the game without cheats......My question is in the cheats they say to press back....how? Back on the left thumbstick or D-pad or what!?!?
Please help?

[Variation-XBA]

Look beside your start button

[natjon]

Thanks for the quick reply!