Each of these pages is the top of a hierarchy of pages. You could wander around each section, picking an entry from the top level and then clicking on various links within the article, or article tags, that strike your fancy, and so on. This is a fine way to introduce yourself to urXron. However, it is unlikely that you would get a comprehensive education on any of the three parts in this fashion. To remedy that, there is a linked tour for each complete section. Note that some of the articles will be stubs, and of course new information will be inserted/updated in the tour links all the time. The Obsidean Portal staff could assist with some additional technology, (i.e. where you sort the "all pages’ list by order of last updated time).
To follow the tour, there are links at the top left of each page that will take you Down(if present), Next, Back, and Up. By just hitting the first link (either Down or Next), you will proceed through a complete tour of the site.
This same tour links are replicated, with some additional descriptive information, at the bottom of the page.
The "zero"th link is “down” to the page’s first child (if it has one).
The first link is to the “next” sibling of the current page, or if there isn’t one, then its parent’s next sibling (and so on).
The second link is to the previous page of the tour.
And a third link if present, is to the page’s parent (if different from the second link).