Hi
You can edit the popup, then set the trigger mode to “when click the specific element”, then, add the button class or ID (let’s say your ID is #apply_now_button) into the trigger object field. https://www.dropbox.com/s/fa7rjx4udz13ydd/Screenshot%202017-05-23%2017.38.42.png?dl=0
Currently, we have only tested the plugin with kingcomposer page builder.
If you still can’t get it work, please post your link and wp login details via private reply, I will check it.
Thanks