Clever Document Links supports two Authentication Types for SharePoint: Client Secret/ (referred to as Client Credentials if using SharePoint Legacy) and Certificate.
If you previously used Basic Authentication, this is now deprecated so the best solution would be to use the Client Secret/Client Credentials option going forwards.
For both Client Secret and Certificates, the SharePoint URL, Scope and Library Name are the same.
In the case of Client Secret Authentication Type you need to specify the Tenant ID, Client ID and Client Secret data from your Azure Account.
If Certificate is used, the same Tenant ID and Client ID are required as well as a copy of the certificate (.pfx file format).
This setup is first done in Azure. Instructions can be found here for this.