To enable event autoresponders:
  1. Navigate to Content > Events
  2. Select the Event List tab
  3. Enter the name of the event
  4. Click Filter Events
  5. Under the Actions column click Edit
  6. On the left hand navigation pane, select Customize Autoresponders
  7. Under the Actions column beside the autoresponder type, click either Revert to Site Default Version to send the site default Version, or click the Switch to Customized Version to send the customized version

Whether you opt to use the site default or the customized version, you can click Preview under the Actions column to see what the autoresponder would look like.