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In the left lower corner of every panel related to an individual ad media item, you will find three menu items: the click URL, the link options and the landing page. To check whether the additional parameters have been added, you can either click on it and see whether the parameters appear in your browser, or you can rightclick on the menu item, save the target URL and copy it to an editor.
You can call the target URL in preview mode just adding at the end: &preview_mode=1
For more information about the preview mode, please read this article.