How to distinguish the "left opening" and "right opening" of the door referred to in Feng Shui?

Opening the door on the left inside means that people don't need to use a key to open the door indoors. The door lock is on the left side of the door and opens the door indoors, while the door lock is on the left side of the door and pushes the door in the direction of the city. Opening the right inner door means that people don't need to use a key to open the door indoors, lock the door on the left side and open the door in the direction of the city.