You can find an answer to virtually any question or problem you run into by Googling "Google Sites [insert key words of problem/issue here]" and various help pages and message boards will pop up. Explore these if you run into unique issues or have questions about customizing features. In the meantime, here are some links to helpful websites/pages that address common needs.
If you have any technical issues not listed here, just email Mary and she will connect you to the EHP webmanager.
Advanced Editing and HTML
Google Sites does not require knowledge of HTML to use. However, if you desire to do advanced edits on certain elements on your pages, you will have to work directly with the HTML code. When in Editing Mode on a specific page, you'll notice an "<HTML>" button at the end of the toolbar. Clicking this will give you access to the code of whichever page section you have selected.