The folks over at TeacherCast.net have two excellent resources for those of you who may need an introduction two Google Sites.
Firstly, they have an introductory video with the very basics:
And then, they have a Google Site of their own, with a number of extra, more advanced features that you might want to consider for your own Site. These include examples of how to embed various items onto your webpages, how to duplicate pages, and other hints for beginners.
This is a site built for teachers, but it will still help you to understand the basics of Google Sites.
For these more advanced features, check out TeacherCast’s What can Google Sites do?