add link to custom field

Hello,

I am not sure there is a built in solution that meets your needs exactly, certainly not with regard to launching a popup.

My first idea for how to go about this is that you should write some custom HTML in a text widget and place the widget to display on the detail page. You would have total control over the elements and markup. That could be accomplished without editing templates.

If you want a project then you could also make a predefined field that does exactly what you want, and an example of that is here: https://wpgeodirectory.com/custom-field-improvements-in-new-v1-6-6/

Either one of those will get you part way, but you may still need additional pieces for the popup. You can also edit the listing-detail.php template and add what you need in there. You can find instructions for modifying templates here: https://wpgeodirectory.com/docs/customizing-geodirectory-templates/

Let us know how it goes, and write back if you have more questions