F1 - Activate Built In Cheats
Uncover All Enemies
Disable Uncover All Cheats
Make My Units Invulnerable "God Mode"
Spawn Super Monster
Spawn Work Force
Spawn All Monster
Spawn All Turned Heroes
Spawn Random Hero
First start game then open the trainer, Then activate the cheat in game.
Once the cheat is activate Press "~" key to bring up the game console on the upper left click on Cheats next to console then press on any cheat you like.
I wouldn't lose any other stuff under cheats other than the stuff listed above.