With the 'wait' command, your dogo can move anywhere in the kitchen, but cannot leave. A little bit at a time, start to back up farther away from the door. If your dogo tries to come through the doorway, walk back to the door, with him in the kitchen and repeat "wait". Stay close to the door until you feel he understands; then back up a couple of steps. If he does that well, then you can back up more. Remember, these steps should be done over several days. Don't expect your dogo to learn it the first day.