How to investigate the Broken Dance Garden? I think all the clues have been found. Then why didn't the plot progress?

Go back to the protagonist's room after the gym investigation, and then go to the bathroom after the bedroom investigation (there are three places in the bathroom to investigate: the nozzle hanging on the wall, the body of the dance garden, and the number above the palm on the right side of the body of the dance garden)

When you go out to investigate and then come in, you will find that the nameplate of the protagonist's room has been replaced by the nameplate of the Dance Garden. In the room where you find the nameplate of the Dance Garden (the nameplate is the protagonist himself), you will be prompted that the nameplate of the Dance Garden has become your own, indicating that someone has changed the nameplate of the protagonist with the nameplate of the Dance Garden.

Then talk to people around you, and then go to the garbage dump. The black and white bear will jump out and say that he can't enter without the key (the key is only for the students on duty). Then you go back and tell them that it's fatty's turn to be on duty. Then you go to the fat man, and he will take you to the dump. Then after investigating the garbage dump, I went to find the super funny fortune teller with long hair fluttering and bending like a snake. After talking to him, it seems that it's almost time to enter the sentence (ps: