Step 1:
The used paper is 6x6inches, prefold in half over the purple lines

Step 6:
Make sharper folding lines into the right directions.

Step 5:
Repeat steps 2 to 4 in this direction.

Step 2:
Fold the edges to the centerline

Step 4:
Fold to the centerline one more time and unfold the model

Step 3:
Fold the edges to the centerline

Step 10:
Fold over these purple lines

Step 8:
The yellow square is the top of the hat.
Fold over the purple lines, use the prefolded lines as help.

Step 9:
Fold over the purple lines, use the prefolded lines as help.

Step 7:
Make sharper folding lines.

Step 16:
Fold over these eight lines.

Step 15:
Use the prefolded lines as help

Step 12:
Press the corners outwards from the inside of the hat.

Step 11:
Glue / tape the edges around the purple square together

Step 14:
Make a sharp folding line around the top of the hat.

Step 13:
Press outwards a little further