Step 1:
I folded black crepe paper around normal paper squares and attached the crepe paper with transparent tape. The normal paper makes the folding of the crepe paper easier.

Step 6:
Fold over the prefolded lines into a basic shape. Start with the two lines at the bottom right and work in the direction of the two arrows.

Step 5:
This is the other side. Prefold over the four lines.

Step 2:
Prefold in half over these four lines.

Step 4:
Fold the corners outwards.

Step 3:
Fold the corners to the center.

Step 10:
Turn the model.

Step 8:
Sink-fold the center over the prefolded line.

Step 9:
Press a little further inwards, see arrows.

Step 7:
Prefold over this line and open the model, see next photo.

Step 16:
First, I attached some flowers to the dress using safety pins.

Step 15:
I made my flowers in three different sizes, the largest are for the lower hemline. And the two smaller sizes are for the waist line.

Step 12:
Repeat step 11 on this petal.

Step 11:
Squash-fold the petal by folding over these two lines.

Step 14:
Fold the tip of each petal backwards.

Step 13:
Repeat step 11 on the other six petals.

Step 18:
I attached the smaller flowers for the waistline the same way: First some with safety pins and the remaining glueing to them.

Step 17:
I glued the remaining flowers to the ones attached with safety pins,
so I spoiled no glue on the dress itself.