In order to use this plugin, you will have to generate a token for the Facebook Conversion API.  You can generate one from your Facebook Events Manager using the instructions here:    https://developers.facebook.com/docs/marketing-api/conversions-api/get-started.  Additional helpful information on the Facebook Conversion API and it's requirements can also be found at that same URL.  You will then need to add the Conversions API element to the page(s) on which the conversion events that you want to send to Facebook are happening.  
As Facebook Click ID is a required field, you will need to be sure to run a workflow to capture the Facebook Click ID from the desired landing page.  You can do so with a Get data from page URL WHEN Page is loaded and save the parameter "fbclid" as a custom state.  Be sure to send this parameter to a new page if your workflow requires you to navigate to a new page on your application.  

From there,  you will need to run the Facebook Conversion API - Prepare Data action to format the data in the way that the Conversion API requires, temporarily save the data using a Set State workflow, and finally, a Facebook Conversions API - Send an event workflow so send the conversion data to the Pixel you have designated.  

NOTE:  Please make sure ALL fields are filled up and you are not sending any empty fields or you will receive an error.  If you don't have access to that information, please send generic information.