How do I navigate this site

If you can't access pages due to login required then check Help:Contents for a list of pages that are public.

Well you can check recent changes to see what has been added or changed recently.

You can check all pages. Notice that you can search all pages for different namespaces.

You can check new pages. Also here you can change namespace to all to search for all new pages.

You can check article list and latest broadcast.

You can check all categories.

Or you can search the site. By clicking advanced in search you can select which namespaces you want to get search results from.