How can we integrate OCI Identity Domain Authentication with our ADW database?

I am reviewing documentation and I've watched the video's below in an attempt to understand how we link our ADW DBaaS service to one of our identity domains so we can manage accounts and authorizations to the ADW database via the Identity Domain. However, It seems that in order to enable the ADW database for integration with an identity domain, we simply execute the command below in the database. We have 8 identity domains, so how does the ADW database know which identity domain it's being associated with?

exec dbms_cloud_admin.enable_external_authentication('OCI_IAM') <-- that is isn't Identity domain specific, so which domain will be associated?