How to determine the three-in-one feng shui?

First, you need to know how to use the compass. Second, you need to know something about geography, such as the mouth of a mountain, and so on. Moreover, you need to know something about Qi, which is a theoretical course. So it will take at least three to five years to study these things. This is the quickest way. It's best to find a master to take you all the way and avoid detours.