I must admit i did not really go for tutorials when i first started learning blender.
Even if this modelling time lapse isn't what you want to model in Blender i think it says more about modelling, approaches to modelling and retopology (after the z brush bit) than quite a few of the tutorials i have subsequently watched.
If in doubt just start modelling a hand in mid air and end up with the right number of edges to join to the arm! Using the sculpt brushes to shape the low poly mesh e.t.c.
it was definitely, mind blowing.
Regards