Make creases by folding the outer edges to the middle line. Flip the model over. Fold in half along the valley fold.
34
The next fold is tricky. Fold up along the crease that is half way between the lower triangle's bottom edge and the top. As you do this release point, to look like figure 35. Turn the model over.
35
Once again fold up along the crease that is half way between the lower triangle's bottom edge and the bottom of the upper triangle. As you do this release point, to look like figure 33. Turn the model over.