Configure microsoft teams incoming webhook json payload

I am trying to set up an incoming webhook to a Microsoft teams channel using the incoming webhook connector. The payload that I am trying to send from my platform looks like this and is form CleverTap (which is failing so I'm trying to debug it using postman). but I am getting the error Summary or Text is required.

{
  "profiles": [
    {
      "email": "jack@gmail.com",
      "identity": "foo",
      "objectId": "-g55b74fb1030740e4a4931910a8abb862",
      "profileData": {
        "Last Score": 308,
        "High Score": 308,
        "Replayed": true
      },
      "name": "Jack"
    }
  ]
}

1. What am I doing wrong?
2. will I need to change the JSON payload according to the adaptive card syntax for teams to accept the incoming webhook? If so, where can I add my custom payload in the adaptive card JSON body?
3. are there other authentication factors at the webhook endpoint (do I have to whitelist the ip address from where the POST message is being sent from)?

To send a message using incoming webhook, you must post a JSON payload to the webhook URL. This payload should be in the form of O365 Connector card. Payload of any other format is not acceptable in Teams. Here is an Example Connector card that you can post. You can now also send an Adaptive card using incoming webhook. Please check the docs here.