Having used Group Policy almost every working day of my life it is easy to forget that sometime the basic stuff is still a challenge to get your head around. Therefore Microsoft has just released a document (and web page) that is an excellent primer for anyone just starting to use Group Policy. See links below.

Introduces Group Policy, provides an overview of what you can do with Group Policy, describes essential concepts that you must know, and provides step-by-step instructions for the most common Group Policy tasks.

HTML Version: http://technet.microsoft.com/en-us/library/hh147307(WS.10).aspx

Docx Version: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=470526da-8350-4314-a48d-ca97721855e1