The main function is psychological comfort, which makes you feel fully prepared and avoids mental stress or panic.

Whether it is useful or not depends on your mastery and application of the knowledge in the book-you can adapt to the new environment as soon as possible and communicate with people smoothly in the new environment, which is enough-the role of language is to help people communicate smoothly.

So I suggest that you don't have to bring books and CDs, and you may not necessarily read them if you do-you have a new learning task and a new understanding of English learning in the new environment, which is of great help to improve your English level.

I wish you happiness! O(∩_∩)O~~