The son of a knight did not usually go to school (in fact, very few children in the Middle Ages did). Until he was seven he might be taught a little by his mother or a priest at home. Then he would be sent to live in the castle of another knight and his family as a page. A page had to learn how to serve at his master's table, and how a castle was run. He also learnt how to ride well and to handle weapons.
Boys learning to joust on a wooden horse
When he was fourteen, if his master was pleased with him, the page might become a squire. The word 'squire' comes from the French word 'escuyer' meaning 'shield-carrier'. The young squire learnt about how to be a knight by going with his master to war, carrying his shield, putting on his armour before the battle, looking after his horses. The squire had to keep his master's equipment ready and bring it to him when it was needed, even in the midst of a battle.
By the time he was twenty-one, the squire might be made a knight, and hope to be given some land by his liege lord. Otherwise, he would have to find some other way to make money, since horses and armour were expensive, and knights were expected to be generous. He might try to marry a rich woman, or hire himself out for pay as a mercenary fighter.