POPUP PRO - OPEN POPUP ON BUTTON/PHOTO CLICK

The plugin is installed. I want to open the popup on a button/photo click. I do not follow the guidance provided in the forum here:

https://premium.wpmudev.org/forums/topic/popup-pro-open-popup-on-button-click?utm_expid=3606929-101.yRvM9BqCTnWwtfcczEfOmg.0&utm_referrer=https%3A%2F%2Fpremium.wpmudev.org%2Fforums%2Ftopic%2Fhow-to-use-pop-up-plugin-on-buttonlink-click-to-appear

Please explain in greater detail how to setup the popup.

Thank you,

McKinley