Here is a example how to pick a Offer and create a new Pixel/Postback, with any Event, Type and write a URL/Code.
On this video you start on the home page, click on Offers / Browse offers, click on Details of the Offer you want to see. Here click on third-party tracking, and then click on New Pixel/Postback. Here choose an event, choose ''any event'' and than choose ''Postback URL''. On URL/Code write http://www.myCounter.com/?Event= and in menu below look for data you want to have in this link.