You begin facing a bunch of bookshelves, turn to your right and exit this room, there will be a piano in front of you, take a step to the left of the piano towards the steps, now you will see a corridor, go down the doorway that's on the right, you will see a long walkway, and a gate to your right, go down this walkway and you will stop next to the small circular cactus' on the ground, and you're done.