Instructions
Reach the plow shed in the game. Go up to the lock and use the code "Diamond," "Diamond," "Diamond," "Star," "Star" to open it. Go inside and you will see Greg standing there. Talk to him and he will explain a few things and instruct you to go to the general store.
Exit the plow shed and go to the general store. Here you will meet Tommy's dad. Speak to him and he will give you more information and tell you to find the blue quartz. Go back to the plow shed, but don't go inside; instead, go around to the back of the shed.
Tap on the areas where coal is piled to check for pieces of coal that contain the blue quartz. Tap the pieces of coal until one cracks open to reveal the quartz. Go back to the general store and trade Tommy's dad the quartz for the coin. Go over to the statue and get the page with symbols, and then insert the coin into the slot at the bottom of the statue.
Go back outside and you will see the entrance to the maze is now open. Go through the maze until you meet Nero and talk to him. After the conversation, continue through the maze until you reach the manor garage. Talk to James and he will show you the iron puzzle box. Select the symbol that looks like an arrow to open the box.