There are a number of resources you can consult when working with occam2.
Daniel Hyde has written a good primer (PDF) that provides additional history and an introduction to the basics of the language.
Pountain and May's text (PDF) on the subject is concise. Burns (PDF) is a bit more verbose, but not overly so. Both are good books on the language.
Other resources may be found about the WWW, but those are where I would begin. I will provide a brief primer here for your first MiniLab.