Point your browser to idx.cgi?file=some-new-page or idx.cgi?file=some-other-page and this creates a new document. To edit the new document, click 'edit' at the bottom of the screen.
To make links to documents, use A HREF like in html, but with all square brackets instead of less and greater than signs. In the future lufdoc will have a shortcut way of making HREF's, such as |FILE:somepage| and adopting some of SimpleWiki syntax.