Configure app within M365 - Application based permissions - Certificate Based (recommended)
The preferred method to authenticate with the graph api is via application based permissions.
Using M365 SharePoint as a Gimmal Link Enterprise repository you will need to ensure that the Enterprise Connector is configured and able to connect to the Microsoft graph API. You must create an enterprise application via the Microsoft Azure portal to complete this procedure. This will require an account with appropriate level of permissions to grant correct access rights to a user (connector user) using the graph API when inside the azure portal.
You can either self-grant access or have an admin grant access to the graph API and its corresponding access rules inside the azure portal if and only if that user has authority to grant access to those rules.
The following steps below outline this process:
i. Visit https://portal.azure.com/ then login using an appropriate account.
ii. Click on Active Directory, then click on App Registrations and click on new registration.
Name the application GimmalLinkENT_suffix (Either DEV, TEST,PROD) depending on environment provisioning.
Select single tenant.
Click register.
Click Api Permissions under Manage.
Click Add Permissions.
We have also included a summary of the site level permissions here
Click Grant admin consent for GimmalLinkENT_suffix app
Click certificates and secrets.

Click on 'Upload certificate' under 'Certificates' tab.

select a public key/certificate by selecting it via file choose.

Provide appropriate description of the certificate in 'Description' field.
Click on 'Add'
If everything is well, certificate basic details will be populated in the table along with Thumbprint, Description, start date, Expiry Date and certificate ID.

Click on overview and save the following information. App ID, and tenant ID.