The people in the villages in the ancient African kingdoms believed that one god ruled, because obviously, no one god could do everything by himself. They believed his assistants, the lesser gods, might drop by at any time and check on them. To catch the eye of a passing god, so that he would stop in and make sure they had what they needed, they danced and sang and shook rattle and beat drums and carved masks. The people believed their method of talking to the gods worked because they were mostly very happy in ancient times.
They also believed their ancestors could talk to the gods on their behalf.
They believed in magic. They believed the local witchdoctor could perform feats of magic. People would visit the witchdoctor to find help for their problems. The witchdoctor might give them something magical to wear, or bury, or give away. Witchdoctors knew a great deal about herbs and home made medicines. Their magic spells sometimes worked. The witchdoctors also knew a great deal about the power of suggestion, and that helped as well.