Before You Begin Reading: A Word of Advice - DON'T PANIC
The SCA may seem confusing at first, when you discover there are certain forms of address for certain people, rules about what to wear and what not to wear, and even customs about what to say and do in court. That can be scary! However, nobody expects you to know everything before you begin. Everybody learns as they go, and everybody makes mistakes. It's okay. Just be pleasant, be courteous, and be yourself. You will make friends, learn how to fit in, and have a great time!
Newcomer's Resources at sca.org
Under Resources on the sca.org website, there is a link entitled "Newcomers Resources." This is an awesome link, but it provides you with an overwhelming amount of information. With dozens of links and downloadable pdfs, where do you begin?
If you're planning on attending an event in the near future, sewing is a high priority. I suggest you begin by looking at some photos. The "Society Chateleine's - Photos" Page is a great place to start. This will give you an idea of what garb (medieval and Renaissance clothing) looks like.
After you have an idea of what you want to sew, visit "Introduction to Garb" on the Newcomers' Resources page, heading "What to Wear." This will take you to Mistress Cynthia de Pre's Argent's excellent site, complete with patterns and advice on how to make or obtain accessories such as belts.