How to create PBI API Authorization header from AppID and Secret?

Thank you for the resources. I've read through them.

My challenge is trying to access the PBI REST API from outside PowerBI (from Power Automate in this case).  In the video example you shared, the person is using the Client_ID from their Azure registered app along with their own Username and Password to generate an access token. 

This will not work in my case. 

I need to generate a token with Client_ID and Client_Secret. How is this done?

The error I'm receiving is Invalid Client Secret (though I've checked and double checked that the secret is correct):

{
  "error": "invalid_client",
  "error_description": "AADSTS7000215: Invalid client secret is provided.\r\nTrace ID: 947ff77d-fc36-480d-a58c-011c126e7400\r\nCorrelation ID: 2af5df99-2ff6-41cb-a094-ca7d5750ef99\r\nTimestamp: 2021-02-24 17:30:39Z",
  "error_codes": [
    7000215
  ],
  "timestamp": "2021-02-24 17:30:39Z",
  "trace_id": "947ff77d-fc36-480d-a58c-011c126e7400",
  "correlation_id": "2af5df99-2ff6-41cb-a094-ca7d5750ef99",
  "error_uri": "https://login.microsoftonline.com/error?code=7000215"
}