Generally, you need a library card and swipe your card to enter. Our school is like this. If you forget your card, you can register for the college and learn to enter.

Schools that don't need to swipe their cards are usually guarded by doormen, so you can still go in, as long as you go in publicly.

You need to feel the atmosphere of the university. You can go to the study room of the university, that is, the classroom where no one is in class. The environment there is also quite good.