There's a guide in dev log! But just in case,
- Orc clue #1 - Examine the magic book in its room, then check the cipher panel in the mural room. Return to the book's room and acquire it. Read both murals. Use the acquired magic book's contents to decipher the left cipher on the panel and deduce the meaning of the right cipher. Execute this deciphered code on the mural. If you're stuck, a answer is (push something at the bottom left side), allowing you to interact with one of the murals.