Hi, congrats on becoming the administrator of this wonderful website.
Site Setup
Here are the first few options you should immediately set upon tweaking:
Basic site information
The administer menu is on the right, and works the same as any other menu.
Go to: Administer - Site configuration - Site information
Edit all relevant information. Please put YOUR email address.
You may choose to leave the Site name blank if you have a logo.
The header
The header is a block. To edit the header,
Go to: Administer - Site building - Blocks
There you will see a list of blocks. Some blocks are activated and put into regions. Most are not. Ignore most of them for now, find the region 'header'. Find the block 'Header Image and Text'.
Click Configure.
In the main Block Body you will see the code for the header. The is a 'div' tag. This is an html element that denotes an area on the screen. It has both height and background styles. You may edit both to your liking. The background style, that is, the direct link to the image inside the parenthesis after 'url', is the header image. You may upload an image onto the site or anywhere else to put as the background there.
The [view:header] is the code to call the overlaying text. Do not touch this. We will come back to this later in the General Admin Handbook (Just right after this

) section.
Once you are done with your edits, click Save Block. You should not have altered anything but the height and the background (if you altered anything at all).
Choosing a theme
Go to: Administer - Site building - Themes
Here you choose your logo.
Site Content and Settings