This is the most important part of the navigation item form - the link. This must be entered exactly and can take one of two forms:

For links within your web site

/path/to/path/
or
/path/to/page.php

You can skip out the "http://www etc" part and start with just the path. This is because your web site will assume any links withou the http are internal links If you are looking for a link to a content managed page the filename and paths are listed in the main content manage menu.

For links off your web site

Links to other sites must ba a complete URL - like http://www.pawprint.net/ Keep in mind that except in the case of portal type web sites - it is rare to include off-site links in the main navigation.