First of all, you should attend the necessary training. Although the exams are all multiple-choice questions, it's good to have someone to help you draw the key points. In addition, the course of educational psychology is very useful. Listening is informative, but don't miss class.

Secondly, exam books can be purchased at the registration site or online, but personally, it is best to buy second-hand books. After all, there is a point (if there is no time for class).

The third question about the major is that you must write it when filling out the application online, but it has nothing to do with the major and has no influence (except those who graduated from normal university). The subject will be indicated on the certificate.

Fourth, if you want to change your major, it involves the type of certificate you need to take. If it is not a big problem of higher education, the general education system (primary and secondary schools) may have an impact, but don't worry, because I have seen cases where the teachers who actually teach do not match the subjects on the qualification certificate.