This library wraps the Graph API by Microsoft v1.0. The library can authenticate as a service (NewKeyClient) or as a delegate for a user (NewClient). The NewClient function will launch a browser for the OAuth2 authentication flow. This will obviously not work with a web application and slightly different API will be needed in such a case.
An Application must be created in Azure Active Directory in order for OAuth2 to work. This registration will get you a client ID and client Key to be used. See https://docs.microsoft.com/en-us/graph/auth-register-app-v2 for steps and more information.
To get the Tenant ID, see https://docs.microsoft.com/en-us/onedrive/find-your-office-365-tenant-id. The Tenant ID is a UUID like 8978cef5-80eb-4282-a783-642044e5f373
There are some examples in the examples folder to assist with learning the library.