it's free why don't you just download it directly from Microsoft's site.
if you already has SP2 or 1. that's enough.
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=2fcde6ce-b5fb-4488-8c50-fe22559d164e&displaylang=en
it's upto you to read what I have posted and understand the concept behind it.
I spent couple of minutes with ms paint to write these equations.
so get advantage from it.