It is located next to Wan Ren (Guanchouyuan Dining Hall), in the northwest of the center of the school. When you get to the northwest gate, go straight east and cross the playground to a fork in the road (it's hard to describe, ask someone), and you will see it. It is on the second floor of a building, next to a coffee shop. Ask a student about Shan Shan Academy, and you must know it.
I suggest you come by bike. There are other bookstores in the garden, you can go and have a look. There is one under building C, and there seems to be one under ten thousand people, but I haven't been there, so I'm not sure.
I hope it helps you.