David,
In the Microsoft Graph module, there are some microflows that access Graph API functions using the authorization information. You can use these as an example of how to use the Authorization information. One of these microflows is SUB_User_GetMyPhoto. Walking through this microflow, you'll see that an Authorization object is passed into sub microflow Get:
Inside of the GET microflow, you'll see that the Authorization token is decrypted and then used as an Authorization header in a REST call to the GRAPH API
You can repeat this pattern for all of the GRAPH calls you need to make.
Hope that helps,
Mike