1. The so-called sitting facing south means that the door of the house faces south, so the back of the house naturally faces north. Sitting facing south doesn't mean being in the north, but the back of the house faces north and the door faces south.
2. In the house, facing the door, the direction of the house is the direction you are facing at this time. This is called "Xiang" and the position of the house is called "Left". Then the house facing south is the house facing north and the door facing south.
Modern architecture is no longer in the form of quadrangles, and in fact it is not what it used to be. Sitting facing south basically means that the main functional rooms (such as living room and master bedroom) of the house are facing south, or the main lighting surface of the house is on the south side.