This video explains how to add and manage Workouts in the Library.
Coaches can now create Garmin-compatible workouts in the Library. When these workouts are assigned to an athlete's calendar, the workout will also be sent to the athlete's Garmin Connect account (if the athlete has connected Garmin and RunDNA). See Connect Wearable Devices and Using Garmin Workouts for more details.
Note: Editing a workout will also update all related workout instances on an athlete's calendar. You can Clone the workout instead if you want to create a similar workout.