If you forget, the system will automatically create both the Subject and the body of the Confirmation email. These are fairly basic, but will totally work for any registration.
Notice that the name of the organization is in the Subject and email replacement codes are in the body. Of course, you may want to customize these yourself, but you will no longer be embarrassed by forgetting to create these.
If you shy away from creating online registrations, check out our revised help article for creating a basic registration. It contains 3 videos : one walks you through creating a simple registration, another shows you how to test a registration, and the third shows you how to capture the URL to post on your public website.