1. First, bring a ruby and a prop called a box. You can check the box first, move the mouse to the box and click, and select "Check" in the menu that appears.

2. Secondly, you can find that a piece of jewelry is missing from the lid of the box, so move the mouse to the ruby and click the left button, then select and click "Combination" on the menu that appears.

3. Finally, move the mouse to the box and click the left button. In this way, the two will always be combined, and the ruby will be placed on the lid of the box!