I don't know which URL paste in the RSS feed. When I try, I get the following error:
Production RSS Feed
Connect your RSS feed for Insntant Articles here. Learn more about automated publishing options, including API.
Unclaimed URL
The URL
https://example.com/feed/
has not been claimed for Instant Articles. Please check to make sure you have a URL registered for your page. For more information refer to URLs in the Publishing Articles section of the Instant Articles documentation.RSS Feed URL