1. Pick up the book on the floor.
2. Pick up the ink.
3. Obtain the wooden fork off the statue.
4. Use the fork to obtain the pen from the hole to the left side of the room.
5. In this step, dismantle the book first to obtain a piece of paper. You can then place the paper on the tab to the right side of the room. Combine the ink and the pen. Use it to sketch and obtain the numbers on the paper. Remember to pick up the paper with numbers on them.
6. Head back to the center table. Place the written note and move the plate. You will be able to see numbers along with different codes. You can use these information to obtain the code to unlock the door to the back.