05.
Turn the paper over.
Prepare to apply four valley-folds.
Two triangle points will be merged on the line (1).
Two diamond points should be merged on the line (2).
06.
Apply four valley-folds of the step #5.
Make sure that the triangle corner points should be on the line (1) while the diamond points on the line (2).
Prepare to unfold four valley-folds.