What’s the API full process for subscribing a Facebook page to an app?

I need to allow users to easily subscribe their Facebook page to my app (which uses webhooks).

I’ve found incomplete posts, largely talking about first gaining an access token for each page, but surely there must be a way to process this via the API, so it’s easy for users? The process would be:

  1. User clicks ‘add my page’ on my web platform
  2. Redirects to Facebook, and asks user to select the page they wish to connect, and grant permission
  3. Returns to my platform and adds the relevant info into the backend, ready for the incoming calls

Is there anywhere this flow is documented? I’m using the NodeJS SDK

Source: Facebook SDK Questions