This is extremely important, and I must say it first: don't trust the bookstore's own mini-program for booking a visit at a specific time. The description said there was a 9 PM visit after closing time, but I booked that one. Luckily, my itinerary ended early, and I arrived around 8:30 PM, only to be told they were closing and I should go to the second floor first. Closing time was 9 PM, and I almost missed it!
Remember to wear shoe covers once inside. They're in the basket on the right. Put them on before entering. The bookstore is quite spacious, with the second floor being the main attraction, perfect for taking photos.