Singing, music and dancing were essential at feasts, fairs and in church. Singing was often combined with dancing. People danced together in a ring, singing. They often danced hand in hand in a long row. Singing-games were common. Dancing two and two together was very unusual in the Middle Ages. Everybody took part in the dancing. Usually, one danced out-of-doors, perhaps in an open field. In town, one might dance in the square as the houses were too narrow and dark for dancing.
People took every chance to dance: at family events like a christening or wedding, at religious celebrations or whenever a minstrel or musician came to the village. Dancing was an important way of letting go, in joy and happiness or in sadness and disappointment.
The one who led the dance might play the flute or the drum. The bag-pipe was also popular.
People danced in church as well, especially at great events and celebrations.
If you want to know more about medieval singing and dancing, read "Town Life. Workdays and Holidays."