Hit enter to bring up the message box then type in the following:

Code - Effect
Army Creep - Invulnerability Cheat (you have to select units before entering)
Love the Gelt # - *Gold Cheat (you have to specify an amount)
Strong Wind - Mana Cheat (you have to select units before entering)
Irresistible Force - Spell Cooldown Cheat (you have to select units before entering, must use each time you want a spell to automatically cooled down)