Piwik requires a configuration parameter and a site parameter.
Go to the application's configuration interface to set upurl on your Piwik server.
General information on creating and configuring a site can be found in the following section of the administration manual: Creating a new site.
Further information on these parameters can be found in the Newsletter section.
In the site settings area, in the "General information" section, enter the Piwik identifier for the site:
If you do not wish to use Piwik for this site, simply leave this parameter blank.