As for the student handbook, just read it before the exam. The examination time is uncertain, so there is no need to take it. Don't worry at all.
There are no other exams, so if you choose a good course, you should be careful about this.
There are fewer majors in Beijing Jiaotong University. You should be able to choose for yourself. There is no psychology department in Beijing Jiaotong University, but there are elective courses.