Sending the correct credential using Facebook Grap Api and Webhooks to received subscribed messages from messenger through django

Question

I'm having trouble wrapping my head around how exactly to use the Facebook Graph Api and Webhooks. I'm trying to send and read messages from a group chat that I'm a part of on Facebook. I followed the steps to create an app on Developers.Facebook.com and passed the app review for pages_messages. I generated a Page_access_token and subscribed my app to my fb page. I imagine I need to give Facebook the actual page_access_token and app_secret somewhere in my code, but the tutorial I followed says nothing about it. I'm using django, and the following code to receive the webhook from Facebook using a tutorial I found online:

class botView(generic.View):
def get(self, request, *args, **kwargs):
    if self.request.GET['hub.verify_token'] == VERIFY_TOKEN:
        print(self.request.GET['hub.challenge'])
        return HttpResponse(self.request.GET['hub.challenge'], 200)
    else:
        return HttpResponse('Error, invalid token')

@method_decorator(csrf_exempt)
def dispatch(self, request, *args, **kwargs):
    return generic.View.dispatch(self, request, *args, **kwargs)

# Post function to handle Facebook messages
def post(self, request, *args, **kwargs):
    # Converts the text payload into a python dictionary
    incoming_message = json.loads(self.request.body.decode('utf-8'))
    print(incoming_message)
    # Facebook recommends going through every entry since they might send
    # multiple messages in a single call during high load
    for entry in incoming_message['entry']:
        for message in entry:
            pass
            # Check to make sure the received call is a message call
            # This might be delivery, optin, postback for other events
            if 'message' in message:
                # Print the message to the terminal
                pprint(message)
                # Assuming the sender only sends text. Non-text messages like stickers, audio, pictures
                # are sent as attachments and must be handled accordingly.
                #post_facebook_message(message['sender']['id'], message['message']['text'])

    return HttpResponse("ok", 200)

Here is the link to the tutorial

https://abhaykashyap.com/blog/post/tutorial-how-build-facebook-messenger-bot-using-django-ngrok

I can send tests from the webhooks to my server and get responses like the following:

{'entry': [{'time': 1535460973, 'id': '0', 'changed_fields': ['message_sends'], 'uid': '0'}], 'object': 'user'

But the samel response that is provided by the webhook looks like:

    {
  "field": "message_sends",
  "value": {
    "id": "mid.86753098675309:uuddlrlrbas",
    "message": "I'm changing jobs for the next 4+ years. Wanna be CEO?",
    "from": {
      "id": 44444444,
      "name": "Lizard Zuckerman",
      "email": "zuck@tehfacebook.com"
    },
    "to": {
      "data": [
        {
          "id": 20061985,
          "name": "Bobbert Cruz",
          "email": "bobbert@tehfacebook.com"
        }
      ]
    }
  }
}

Ngrok does show that there was a successful connection when I receive tests, but I get nothing when I receive messages on my page, even though I'm subscribed to it.