Ask Feng Shui master to help explain the compass.

Compasses can be divided into three types: ternary disk, triple disk and comprehensive compass. But the specific use is the same, and there is little difference. As long as you can use it.

To understand the meaning of each layer of compass, I suggest you buy a book about compass. The most famous books are Understanding the Compass and Understanding the Compass, but you don't have to consider these two books, and I guess you can't understand them either.

China Feng Shui Compass by Mr. Cheng Jianjun is very suitable for beginners.