The PEAK Developer's Guide
You can edit any page by pressing the link at the bottom of the page. Capitalized words joined together form a WikiName, which hyperlinks to another page. The highlighted title searches for all pages that link to the current page. Pages which do not yet exist are linked with a question mark: just follow the link and you can add a definition.
To learn more about what a WikiWikiWeb is, read about WhyWikiWorks and the WikiNature. Also, consult the WikiWikiWebFaq.
Interesting starting points: