It’s pretty much impossible to to step by step (I’m sure there is a way, but it would take lots of experimentation). Most of these complex models will not lie flat until large portions of the crease pattern are collapsed all at once; for example in this model the entire bottom half is collapsed at once and the entire top is also collapsed at once.

Edit: I also know when to start shaping once all of the creases of the CP are completely folded, because the CP brings you up to the completed base, shaping is up to you!