The clergy is the head of the medieval caste system. God gives the power to the church who then crowns the king and supports the nobles who rule over the peasants.
When you enter the monastery, you give up all your belongings. Many rich men on their death beds bequeath their belongings to the church in return for a clean soul. And you receive tithes from everyone. So you generally do well financially. But your resources are drained as you must take care of the poor, of which there are many.
As a young brother, you must work in the garden and made bread to learn humility and discipline. But you soon turn to reading, perfecting your Latin, and writing your own Latin books. You also study grammar, rhetoric, and logic--all taught in Latin. You may receive advanced study learning the quadrivium--astronomy, arithmetic, geometry, and music. You may even learn a little botany or geology.
You probably copy the Bible or other books onto new parchment, which is very expensive. You write by hand in calligraphy. You probably make beautiful illuminated initials to begin new chapters or sections. When you are done, the book will be bound in leather, or perhaps wood. You are not tried before the ordinary law, but by the cannon law by the bishop, which only uses capital punishment for heresy. The worst punishment is being locked in a dungeon.