A polyandrous marriage is when a woman is married to more than one man at the same time. Polyandry typically has less to do with "female power" but more so in African societies where it is practiced, is borne out of socioeconomic necessity. For instance, a woman may need more than one man in order to handle all the duties around the home e.g. farming, cattle-rearing, shepherding, etc.
Among the Lele people of the Congo, because young girls tended to be betrothed to older men, the younger men (who would still be in waiting for their own betrothed brides to reach their teens) could make a request to the village elders that they be given a "common wife", i.e. a wife to be shared by all the men in a given age group. This woman is called a "wife of the village".
A daughter or granddaughter of an older "wife of the village" would be assigned to fulfill this role. If one was not assigned (or not available), then the young men could go to a neighboring village and capture a woman from there to be their wife.
The young men do/did have a responsibility to their wife. They are required to work for their "village wife's" parents and they must also provide a payment to her parents for her. In addition, they have to provide her with her own dwelling place.
"Marital relations" in a polyandrous marriage occurred in order of age and eventually the village wife can choose five or six of the men to live in her house with her. Within her home, she would functions as a traditional wife to each of these men but she is still considered a village wife which means that any of the other men could have marital relations with her and not be infringing on anyone else's rights.
Her househusbands will eventually move out and marry the girls to whom they were betrothed. They would however be responsible for taking care of the children of the village wife. The village as a whole will be responsible to pay the dowry for future wives on behalf of the sons of the village wife.