The finished frog base has four flaps. Close it up neatly. Valley fold the tip of one flap to the top of the model. The crease should run to the midpoint of the lower edge. Unfold to Step 3.
Valley fold the long edge of the flap to the centerline.
Unfold to Step 5. Begin the squash fold. The flap has two layers. Leave the hidden layer in place. Bisect the tip, as shown.