I can't remember what happens to the feather.
Maybe if you click-hold it and move it to the instrument and then click-hold to the next one - maybe that will work.
Also keep repeating 4, 3, 1, 2, 4, 3, 1 and 2... It might click when they are repeated continuously.
The last challenge is setting the intestines (instruments) to play the correct tune. Notice the length of the music played by instruments.
All instruments must be set in such a position to all play the same length of music together. By touching the parts with a peacock feather, you can change the melody played.