The fold is just above the bottom edge. Valley fold the sides exactly to the center. Valley fold and unfold through all layers. Valley fold the corners to the sides to form the collar. These folds extend just down to the existing crease.
Mountain fold the top behind.
It should end up just short of the bottom of the jacket. Holding the model as illustrated, use thumb to roll out paper to form an arm. Repeat to form the arm on the other side. Mountain fold the shoulders behind. Thin out the sides of the pants using mountain folds.