Step 1:
The folding paper is about 20x60 centimeters, two standard size printer-/copy papers glued together.
Prefold in half, then fold both edges to this prefolded centerline.

Step 6:
Make zig zag folds over the prefolded lines.

Step 5:
Fold this part in half two more times.
Then unfold the model again.

Step 2:
Fold both edges to the centerline and unfold the model.

Step 4:
Fold the part on the right in half.

Step 3:
Fold in half over the prefolded line.

Step 10:
Curve both edges backwards and glue them together.

Step 8:
Press the center edge flat (squash-fold), just the upper part of it.

Step 9:
Fold over these two prefolded lines.

Step 7:
Press three edges to the left and three edges to the right. Glue them to the model (just the upper parts).

Step 12:
Fold over these two lines.

Step 11:
Pull the lower edge of the skirt outwards, see small arrows. And press the skirt flat on the left and right part, see large arrows. The two white outer lines show the shape the skirt should get.

Step 13:
Fold over these two lines, the flaps go behind the skirt.