After entering from the door on the first floor (facing east, facing the office building), you can see two elevators, which can take you up and down the whole 20th floor. Of course, if you only borrow books on the first to fourth floors, you don't have to take the elevator. Go straight after the elevator. When you come to an open field, you will see a staircase on your right. Climb to the top and you will see the borrowing desk ~ ~