Heroes or companions are unique troops with individual names, stories, skills, attributes, and equipment (all of which can be chosen by you). Like the player character, heroes never die and are only knocked unconscious. You can never station them in garrisons.
To use cheats, you must configure your game to allow cheats: After opening up the game launcher, before you click Play Mount&Blade, go to Configure. From there, go to the Game tab and check the box next to Enable Cheats.