Tutoriales

I have been looking at this tutorial but I have not understood anything since I can read the commands that it uses.
(https://www.facebook.com/gurioli?hc_ref=ARTAWO0NO9M6UQa3sk7Q6ueMqb1jeQtugJBxo4HIZSz1YXjT6AZxQrYoBsm-j0-nWp8)

_Polyline, _ExtrudeCrv, _Mesh, _SubDDaMesh

Thank you