No, sorry.  We didn't have to use Gtags on our site.  I assume you tried installing the gtag.js file to your site using the Google provided documentation already but running into some challenges. gtag.js Developer Guide  |  Global site tag (gtag.js)

We are not able to see your images, but it sounds like your are trying to setup a Google RLSA. I recently set up a Google RLSA using the following document - Send Segments to a Google AdWords Remarketing List Hope that helps and is what you are needing.