To view which courses use a specific certificate, log in as administrator and from your Administration dashboard, visit the Certificates page.
Here, you will see a tabular list of all your certificate templates.
To view what courses are using one of these templates click on the one that interests you.
If the certificate template is used by a course, a second tab will be available. This is called Used by courses (1). If you click on this tab, you will be presented with a tabular list of all courses that offer this certificate.
Note: If you haven't assigned the specific template to any course, you won't be able to see the tab "Used by courses" at all.