How to use "Show on click rule" Pop Up plugin

Hi,

I've installed the addon "Show on click rule". How should I use this?

If you look at the URL htp://www.wijngaardecoaching.nl, below the slider is a yellow button. I need the pop over to show when someone clicks on the yellow button.

In the backend of the theme I can enter a link to open after clicking on it? What should I fill in here? And what should I fill in "element selector" within the rules setting?

Thank you for your help!

Kind regards,
Steven