To solve the music box puzzle in the Silent Hill 2 remake, follow these detailed steps:

1. **Locate and Open the Music Box**
– Find the Ornamental Key in the Check-In area, behind the clerk’s desk. It is bundled with the key to Room 312.
– Use the Ornamental Key to unlock the music box. This will reveal three empty slots and four plates with tracks.

2. **Find and Install the Figurines**
– Locate the Figurines, each representing a character from a classic fairy tale:
– **Snow White**: Found by completing the Mirror Puzzle in Room 202. To do this:
– Enter Room 202.
– Pick up the Room 202 Key and Ripe Apple from the couch.
– Enter the bedroom and interact with the broken mirror to fix it.
– Place the Ripe Apple on the plate to solve the puzzle.
– Pick up the Snow White figurine from Room 201.
– **Cinderella**: The exact location is not specified, but it involves solving puzzles and exploring the hotel.
– **The Little Mermaid**: Found in the Venus Tears Bar, accessible by using the Pump Valve in the Boiler Room to find the Venus Tears Bar Key, then using it in the Kitchen to enter the bar.

– Install the Figurines by placing each into its respective slot in the music box. The game will not allow you to place them incorrectly, so you can simply cycle through your inventory to place each figurine.

3. **Set Up the Paths**
– Rotate the Plates: Each plate has tracks that the figurines will follow. Rotate the circular sections so that each princess has a track directly to one of the built-in doors.

4. **Wind Up the Keys**
– Identify the Riddles associated with each key:
– **Snow White**:
*What began with three*
*One would soon deplore*
*Seven kindly souls*
*Opened up the door*
Turn Snow White’s key seven times.
– **The Little Mermaid**:
*Trading one for two*
*Away she would roam*
*But the love of five*
*Would bring her back home*
Turn The Little Mermaid’s key five times.
– **Cinderella**:
*Taunted by the two*
*She would toil away*
*Leaving one behind*
*She has found a way*
Turn Cinderella’s key one time.

– Turn the Keys by winding up each key the correct number of times to control the speed at which the princesses move along their tracks. Ensure each key faces the right direction and turn them accordingly.

5. **Activate the Music Box**
– Press the Button: Once you have set up the paths and wound up the keys correctly, press the large button below the music box.
– Complete the Puzzle: If done correctly, all three princesses will follow their respective paths and enter their doors simultaneously, completing the puzzle.
– Reward: After completing the puzzle, you will receive the 3F Corridor Key, which allows you to access Room 312 and further progress in the game.

By following these steps, you should be able to solve the music box puzzle in the Silent Hill 2 remake.