To set an appointment reminder, select the appointment and choose the Create new Reminder option from the menu. The Reminder wizard will first ask you to choose the length of time before the appointment at which the first reminder should be made. You can set days, hours and minutes.
Next, you should check the box if you wish to have repeated reminders.
If the reminder is to be repeated, the next step asks you for the repetition period. You can either choose to have the reminder repeated a set number of times, or you can say how frequently in terms of days, hours and minutes.