Where would an administrator go to check if the Email Sending Domains are set up...

The administrator should go to Admin-Domain Management to check if the Email Sending Domains are set up properly after updating the DNS. Email Sending Domains are domains that you can use to send emails from Marketing Cloud Account Engagement, and they require verification and authentication to ensure that your emails are delivered and not marked as spam. To verify and authenticate your Email Sending Domains, you need to update the DNS records of your domain with the values provided by Marketing Cloud Account Engagement. After updating the DNS, you can go to Admin-Domain Management and click the Verify Now button to check if your Email Sending Domains are verified and authenticated