OKTA OAUTH2 with VBA WinHTTPRequest

I have a small project to upload a JSON data set via API. The API requires OKTA Bearer Token to authorize. I cannot formulate the syntax to get the bearer token from OKTA. I have all the parameters in POSTMAN and I can receive the Bearer Token on its own, and I can combine the token request with the transmission of the data as well.
Need this completed within 48 hours.