Hi ats, and welcome to the forum.
To the best of my knowledge, we’ve never created Scrivener to work with any third-party plug-ins directly. Since we have users from a wide range of disciplines, keeping Scrivener flexible so it can be used with different tools tends to be our approach.
If you search this forum for either “citations” or “mendeley”, you should get quite a few results.
I’d recommend starting with this thread outlining using Scrivener with several citation management tools. It includes Mendeley and has some headings that you can click to show details on a workflow.
This thread also has some Mendeley workflow tips and links to other discussions.