Newbie still having issues querying results

Is there a way to get query results from a passed url variable from another page instead of a text input field? I uploaded my test page to:
http://phantomtranzit.com/registration.php?event=customer+1
When you add the variable to the URL, it does nothing. How do I set server connect input parameters to filter from URL?

Currently I have customer 1 and customer 2 that will display results