Who can explain how the ancients knew the steps of fortune telling (such as using planning or copper coins)

The ancients used yin-yang theory to tell fortune. Everything is based on the theory of yin and yang, such as coins. The front is yang, and the back is yin. The lines in the gossip are also divided into yin and yang, and they are constantly yang and broken into yin. So you can determine the yin and yang by throwing something, such as coins, and then check the records on the hexagrams according to the records of throwing many times. The hexagrams may be formed by long-term experience.