11.

Do steps #7-10 on the other side of the paper so that you have creases that are in the places where the red lines are.

12.

Fold the paper at a diagonal so that there are triangles above the newly folded crease.

13.

Unfold the paper. You will now see a crease going diagonally across the paper (*a green pen has been used to distinctively show)

14.

Do the former 2 steps so that there are 2 diagonals that intersect each other at the center.  Both green and black lines are for mountain folds while red lines are for valley folds.