Hello! In fact, there is no need to take the 6Sigma green belt test. If you want to take the exam, you can take the black belt directly. The black belt is the promotion of the green belt. The green belt only knows six horses. I can give you a Caterpillar internal training textbook, but if you don't have a working foundation, it's very difficult to learn. You can study first, increase your understanding, or find a more systematic training institution to study. You can ask me if you don't understand anything.