Trigger based on Facebook Ad UTM

Hello, I am trying to trigger a Boxzilla pop-up for visitors who have landed on my site by clicking on a facebook ad. I have included a UTM source code in the facebook ad link (utm_source=FacebookAd). Using this UTM code I am able to trigger a popup that shows immediately using the condition “URL contains FacebookAd”. What I would like to do is trigger the pop up after 1 or 2 pageviews, or on the cart page if the visitor has added something to the cart. I ONLY want to show this to visitors who have clicked on this facebook ad, not all visitors from facebook. How can this be achieved?