Step 1:
Prefold in half over both lines.

Step 6:
Make zig zag folds over the prefolded lines

Step 5:
Fold in half one more time, then unfold the folds of step 3 to 5

Step 2:
This is the other side.
Fold over these two lines

Step 4:
Fold in half

Step 3:
Fold the white part in half.

Step 10:
Make four more zig zag folds.

Step 8:
Make an inside reverse fold, use the prefolded line(s) of step 1 as guidance

Step 9:
Make two zig zag folds over the short lines on the right.

Step 7:
Fold the edge backwards and turn the model

Step 16:
Fold the edge inwards

Step 15:
Make an outside reverse fold.

Step 12:
Fold over these two lines.

Step 11:
Fold over these four lines.

Step 14:
Make an outside reverse fold

Step 13:
Fold on both corners

Step 19:
Fold over these two lines.

Step 20:
Fold this edge inwards, do the same on the other side.

Step 18:
Fold the corner downwards.

Step 17:
Fold this edge backwards, do the same on the other side.

Step 21:
Fold this edge inwards

Step 22:
Fold over these two lines.