You start by specifying a string that is found in the URL for which a conversion must be counted, you then associate a conversion number to that string.
You continue with another string for another type of conversion, and so on and so forth.
When a page load, Web-Stat will look at its URL and compare it with the strings you entered, one by one, in order. If it finds a match then we will consider this page view to be a conversion of the number you specified.
Note: you can define up to 10 URL matching strings with the method above. It should be plenty for most people. If you need more please see this document