https://www.youtube.com/watch?v=Nm51v3eaqWk
Gao Zhuang Fei TaiJi tui so - ENG subtitles - Part 1
a good clip with English subtitles
Touches on many of the topics questioned here
with detailed explanation of the what, how and why.
parts of the translation do not quite match with what he says...
over all very well done....