First off, What is a Wiki?
According to Wikipedia, the world's largest wiki site:
A Wiki ([ˈwiː.kiː] <wee-kee> or [ˈwɪ.kiː] <wick-ey>) is a type of website that allows users to add, remove, or otherwise edit and change most content very quickly and easily.
How To Edit Pages - Quickstart
If you are allowed to edit pages in this Site, simply click on edit button at the bottom of the page. This will open an editor with a toolbar pallette with options.
To create a link to a new page, use syntax: new page name or text to display. Follow the link (which should have a different color if page does not exist) and create a new page and edit it!
Wikidot provides a comprehensive site containing Help pages for Wikidot including:
Additional help is available from users like you at Wikidot's Community Site and Community Forum