Creating Web Application + OAuth within Merge
Within the Active Azure Directory portal, navigate to App Registration.
Register a new application for your Azure Active Directory Account.
It is important to mark the application as "Web" and have the redirect URL filled in with the Merge OAuth Callback url! Additionally, the supported Account Types for Merge are options 2 and 3.
3. From here, you will leverage the Web Application you created earlier to fill in the Client ID (Application ID in Azure) and Client Secret.
The Directory (Tenant) ID will be used as the Subdomain when going through the Merge Linking Flow.
The OAuth Redirect URL will be the Merge OAuth Callback URL that you can copy and paste in your linking flow.
Enter your Tenant Id into your Linking Flow
Enter your Tenant ID from the Web Application you created before. Then, add in your Callback URL to copy and paste. After that you are authenticated and ready to go!