One of the first commands most dogs learn is, "stay". Stay is a skill every dog needs to know for safety and general basic obedience. But, teaching your dog stay and ensuring that he's reliable with it takes practice. Here's where to start:
I recommend teaching your release before the verbal command of, "stay". Doing this will shape and capture the behavior of staying in the same spot until told otherwise. Painting a very clear picture for your dog, "stay" means don't move and "release" ('ok', 'free', 'come', etc.) means its okay to move out of that position now that I've commanded it.