In chapter 1 of the game, the player needs to remove 3 more pieces from the mirror by the front door in order to advance. The tree pictures and music box puzzles will give the player one of those pieces.
Video of the Tree Picture puzzle can be seen here: Tree Puzzle on Youtube
Video of the Music Box puzzle can seen here: Music Box Puzzle on Youtube
Tree Picture Puzzle
In the office, go into the bottom desk drawer and pull out the crank, otherwise known as the bird on a branch.
Add the crank to the trunk spot in the pictures and turn the crank counterclockwise.
All the birds will chirp, and you’ll get a music box key to come out of the tree hole. Click on it to add it to your inventory.
Music Box
In the same room is the music box on a shelf. Use the key from the Tree Puzzle to open the box. The bird shadows will light up if it’s done in the correct order.
Inside is a bottle that you’ll use in a later puzzle.