How to get started on the Hivemind wiki
A wiki is completely reliant on the contributions of its users. This means that users create, edit and modify content in an eternal attempt to accurately survey the state of that community. For example, if a new member joins the Hivemind network, they may want to add some pages about themselves. This will then more accurately reflect the fact that this person is in fact a member of the Hivemind. If that person states that they are, for example, quite libertarian in their political views - but through time the other members learn that he or she isn't, another member may then modify that statement about that person in that page.
As another member of the Hivemind, you may be reading these words and think of a better way of explaining a wiki - and then choose to modify it. This page will then, hopefully, do a better job at explaining a wiki than what it is doing at this very moment.
The hivewiki runs on MediaWiki, which is the same system that is used for WikiPedia, the encyclopedia that surveys all human knowledge by means of collaborative writing. Until we have an exhaustive guide on creating and editing pages, you can refer to their excellent guide - specifically with regards to the markup language that mediawiki uses.