At that time it was basically a means of training future priests and holy men. All the schools had to be licenced by a Bishop and the schools were often attached to a cathedral or a monastery. The schools were notably for boys only where pupils would study the trivium (dialectic, rhetoric and grammar) and sometimes the quadrivium. Lessons would have been in Latin and discipline was known to be severe.
One interesting point about education in medieval England was that there was absolutely no class distinction and poor children could rise through society benefited by a good education. Ironically, often the nobility were too proud or sometimes too lazy to educate their children. Upper class boys were in fact more likely to be trained in warfare, usually in another noble household where they would start out as pages.
Despite this, open access to education reading remained largely a preserve of the Holy orders.