Navigating Spaces
 
After logging in, you'll be directed to the Confluence Dashboard, which is the parent of all other pages. While you navigate around within Confluence, you'll notice this within the horizontal Location: link menu. Dashboard will always be the first link in the list:

The Dashboard is like a homepage for the site, but 'Home' is also used for space home pages, hence the differentation. The spaces are listed on the left hand side of the Dashboard under "Your Spaces", and when within a space, the horizontal Location: link menu will use a short space key as the link to the space homepage as the next link after "Dashboard".
Foreach space entry under "Your Spaces", there are a couple of icons of interest:

Cannot resolve external resource into attachment. is for the homepage of the space.
Cannot resolve external resource into attachment. is for the space summary for the space. This shows a short description, recent blogs and updates to pages, reports, and space operations, such as adding yourself to a watch mailing list to be notified of any changes to the space.
Cannot resolve external resource into attachment. will bring you to a list of pages within the site in alphabetical order.
Cannot resolve external resource into attachment. is a link to blog entries in the space.
Cannot resolve external resource into attachment. is a link to create a page in the space.

These links are available on the right hand of any page within a space as well. There is usually an index page for a space as well. That is sometimes a useful page to get around in a large space, but is sometimes hard to find. If a space is small enough, going to the space summary will have the index page listed on the right, under the recently updated section. For a large site, the index can be found through the 'List all pages' link, which will be alphabetical, or, in most cases, under the 'Find all pages that aren't linked from anywhere' link, since most space admins rarely link them.

The important thing to remember with any space is that it is flat, sort of like a directory with many files within it. Most spaces appear hierarchical, but that is only because of links that are set up within pages and if a page is set to have a parent page. That means pages can be moved pretty easily within a space and that there are usually a number of ways to get to a page, so it is usually easiest to follow the Location: link menu described above.