The site details section at Admin Panel -> Settings -> System Settings asks for details about the site you're using WSN as a part of. The URL you should supply here is the main website URL where an inbound link from a link partner should go. WSN might be installed at www.yoursite.com/wsn/, but you'd type www.yoursite.com here to indicate your main site.

The title would be the title you want your link partners to link to -- so, "Your Site" instead of "Your Site's Directory". This will be the default title for the directory too, but to use a different title for the directory title tags you can edit the page titles scheme at Admin Panel -> Templates -> Settings to replace {SITETITLE} with the actual title text you want.

The description should also be what you'd want a link partner to use.

The title and description will be used in the RSS feed by default. You can edit the RSS Feed template (Admin Panel -> Templates -> Manage Templates) to change that to something else.