1, fixed orientation. East is Qinglong, south is Suzaku, north is Xuanwu, and west is White Tiger.
2. Mountain direction. What is the direction of the mountain? For example, the house faces south, so this one points east. On the right is the west. What's sitting facing south? For example, we sit in a chair with our backs on the mountain and our faces facing the other side.
In reality, 80%-90% use, the direction of the mountain. These two points overlap, that is, sitting in a house facing south. The mountain orientation coincides with the fixed orientation. Most houses in China also adopt this design.