From this dialog:
Rename the Email Milestone
An email milestone is likely some type of reminder to the recipient of the occurrence of an event. For example, if you wish to receive a reminder that you must finish a course by a particular date, you may rename the milestone "Correspondence Course Deadline", and set the email to be sent a few days prior to the deadline.
Indicate a date for your email to be sent
By default, today's date will
appear in Date field. To
indicate a specific date, click 
to access a Calendar dialog.
Indicate a recipient address
In order to receive an email milestone, a valid email address must be entered in the Employee's profile. As a Learner, if this has not been done, contact your supervisor.
Enter the Subject and Message Text