Training Plans--Can they be changed?

This question might be better answered in the Garmin Connect forum, but I'll take a stab at it. Once you have scheduled the training plan, it will appear on your calendar. Go to the calendar (on a computer, not the app) and you can drag and drop workouts to different days. It will ask you if you want to move the whole workout or just that day. However it will not allow you to add a workout to the training plan, but you can always add one of your own workouts to your calendar by left clicking the day and add workout.

Also you can click on a workout then hit "edit workout" in the lower right corner to edit specific things on the workout like duration or HR zone or whatever.

When you are satisfied, click the right arrow on the top right of your calendar screen, select "send workouts to device". Assuming it is plugged in via USB and Garmin Express is running, it will transfer the whole calendar over. Well, the next couple months anyway, depending on storage on your watch. You can also transfer them one by one using the phone app and bluetooth but that gets tedious.

On the watch, open the run app then push and hold the up/menu button. Go down to training, scroll down to find training calendar, and pick the desired workout. You can pretty much also do an end run around the whole calendar-adjusting process by just picking the workout from a different day of the training program, there's nothing forcing you to select today's workout instead of tomorrow's.

Hope this helps.