If you see a page on the site which is highlighted in red, e.g. Broken Link, then this means that the page does not yet exist. You can create it yourself - just click the link and you will be taken to the edit page. (This assumes you've logged in first.)
For more information about how the Wiki works, read Wiki Story. Special editable sections are listed in Special Editable Sections. You may also be interested in the Formatting Reference.