Read Yi first, and then read Feng Shui books. If you have a good knowledge of ancient Chinese, you can read Eye of the Underground first, and then Eight Houses Mirror. Remember not to read Feng Shui books in Hong Kong, because people like Hong Kong are no longer Feng Shui in ancient China. "Into the Eye" was written by Song people, which is the essence of the star geomantic omen and the authentic skill of Jade Bird.
It's hard to buy in Guangzhou now. Go to the market and see if there may be.