Step by Step Guide to set up Facebook API Connector

Is there a step by step guide to set the Facebook API connector specifically?

I think I’ve set this part up right

But I have no idea how to do this part

It keeps giving me an error

I’m not technical so the Facebook documentation have not been very helpful. I just need to know the exact link I need for the GET part, and the meaning of the error above?

Hey ! Did you solve this?