You can pass the puzzles under the castle, that is, put the puzzles together, and another way is through the magic mirror.
The magic mirror is in the clothing store on Tao Tao Le Street. A big mirror is a magic mirror. Click it and you will talk, such as you are cool today, and so on. If you click a few more times, he will open the passage to the mushroom hole and you can go through it.
Maybe you will find the right eye of a jigsaw puzzle at 1 1 o'clock, but that won't do, because it's an old jigsaw puzzle.