Create simple popup with Enfold

place on your page – where the popup should do what popup do ;) – a container ( 1/1 ) – fill with your content.
Goto Advanced Tab of that container and give the custom ID to it: myPopup
fill in the custom class: white-popup mfp-hide
so there will be two classes now on this container.

now place on your child-theme functions.php :

function open_popup_on_load(){
?>
<script>
window.addEventListener("DOMContentLoaded", function () { 
  (function($) {
    setTimeout(function() {
      if ($('#myPopup').length) {
        $.magnificPopup.open({
          items: {
          src: '#myPopup' 
          },
          type: 'inline'
        });
      }
    }, 1000);
  })(jQuery);
});
</script>
<?php
}
add_action('wp_footer', 'open_popup_on_load', 999);

change the value 1000 (ms) to whatever you like
see: https://enfold.webers-webdesign.de/selfopen-popup/