In medieval times, most of the people were peasants, farmers who worked all the time just to grow food. They were protected by the Nobles. But who made up the nobility? The Nobility included the landowners, the King, Lords and Ladies, and Knights of the kingdom.
The King: The King was the highest noble of the land. In theory, the king owned all the land. The King gave out fiefs to his followers, which put them in charge of a portion of the land. The fief holder had to pay the king rent, taxes, and provide soldiers whenever the king needed them.
A Lord: A Lord was given a fief by the king. The lord was expected to pay taxes to the king and provide soldiers when needed. To do that, the lord was given absolute power over his fief. Within it, a lord's word was the law. Whatever the lord said, the people had to do.
A Lady: A Lord also needed a wife who was called a Lady. Her job was to take care of the manor, run the house, and most importantly to have children. Women in medieval times had no rights. They were property. They belonged to their father, husband or even eldest son. This is not to say some women didn't take charge, but the law said they were property.
Children: A boy learned how to be a Knight starting at about seven years old. Sometimes they were even taught how to read and write. Girls were not. They were instead expected to learn from their mother all the skills of being a good wife.