When a strong centralized government rules over a portion of land and dictates how their citizens live
Africa doesn't have a good government at that time, they were not yet colonized while Europe had a solid military, on top of that, they had a decent government and were effortlessly ready to stroll into Africa and take control of it.
Do you still need help? If so, I am up for it!
I am pretty confident that the shelters were made from wood and bones. However, I could be wrong, so try to find another source. I hope that my "answer" was useful!
