If he’s using an open/close sensor to see if the gate is open or closed (probably a good idea figuring you don’t want to gate to CLOSE if you arrive and it’s already open), then follow the instructions above.
However, you can side step the whole bit about creating a room and just install my SmartApp (See here: Garage Door Control after v2?).
This lets you just tap the button on the Garage door sensor in the Mobile App to open close the door/gate.