Detailed information about notification configuration is available through various sections in the Administration guide. The following is a summary of the steps to setup email notifications:
Populate fields on any additional tabs that you may require.
Select the Actions tab
In the description add some text (optional)
In the notification section check the "Enabled" box, and select recipients. You can only select a user if you have enabled notifications for that user (see above)
Click "Deploy to Server" from the toolbar at the top.
Note: The rule you just created will fire frequently. Once you have confirmed your email notifications are working you should disable and/or delete this rule.
Please refer to the following KB in order to enable debug logging for the notification service.