Just take your ID card to the information desk on the first floor and you can apply for a library card (if you have 100 yuan, you can borrow three books; 200 yuan can borrow six books. Of course, this money will be returned to you in full when you don't intend to use it in the future. You can borrow books after you get the card. Both the first floor and the second floor are ok, but basically they all go to the second floor.