Early changes in primitive man

How did early man's physiological changes progress from living in trees (arboreal) to walking (Bipedal) the savanna plains of Africa?

Revise parts of the human skeleton 

http://www.bio.utexas.edu/faculty/sjasper/Bio301M/humanevol.html

http://efossils.org/book/what-bipedalism

https://youngzine.org/news/history/fossils-new-ape-species-discovered

extension

https://corewalking.com/chimpanzee-feet-vs-human-feet/