Some of us are students and some of us are teachers. Most importantly, we are a group of friends. Think of it as a sort of role playing, where you adopt the name, culture, dress and habits of a person who could have lived in the middle ages. You act like this character and use this persona as a starting point for your research into the middle ages. Persona selection and development is very individual.
Some people develop it to a fine degree, whilst for others it goes no further than a name.
Go to an event or two and get your bearings. Many new folk don't know much about the middle ages, and this gives them a chance to learn enough to find out where their interest lies. Second, cultivate friends in the group and ask for their assistance. We are a very friendly bunch and don't mind newcomers asking for advice. Third, the persona must be documentably from the period you choose.