Did Zheng He put some Han people there when he arrived in Africa?

No. At that time, it was inevitable that some people would get sick during long-term voyages in tropical areas. In order to ensure the safety of most crew members, the fleet will send sick sailors off the ship and entrust them to local people to take care of them. And leave a map so that he can still return to his motherland after he recovers. Later, the voyages to the Western Seas came to an abrupt end, and many sailors were unable to return home. But the number of people is very small