The rules for basic page editing are fairly simple--start each line without spaces and put a blank line between paragraphs. There are more text formatting rules? for lists and other specialized text, if you want to do that. You can edit the WikiSandbox page if you want to try things out in a way that won't affect any of the pages on this site.
To create references to other pages, [[double bracket]] words to create a page title. This automatically creates a hyperlink. Make titles for New Subjects?, even if you don't have anything to say about them. Maybe someone will come along and fill out a page for the new link.
After you Save a page, you may need to click Reload to make your browser do a refresh. This will let you see the changes you just made. Click the ? after Links? to any new pages to edit them and add text.