I use Final Surge to plan out workouts for those training with me. It's easy to use, has a mobile app and will automatically push structured workouts to your Garmin and means that I can see the data on your workouts automatically. You'll also be able to add notes and comments on a workout.
I'll send you an invite by email to join my coaching program. You'll need to create a Final Surge account if you don't already have one (this is free for you).
I'll add your training plan to your calendar on Final Surge.
You can then connect your Garmin with Final Surge to make sure that workouts are available on your watch - follow the instructions here.
Yes, you're able to do this yourself by dragging the workout onto a different day on your training calendar. If you need help or advice on moving workouts, just ask (you can do this by adding a comment to the activity).