Marking manual activity as a Garmin coach workout

There is a way to merge workouts using "Garmin Connect" and "Fitfiletools.com". You export the fit files from both your manual activity and the Garmin coach workout and you can merge them together.

However I found it way easier to just manually update the Garmin couch workout, you also have to do this from a computer using the Garmin connect website but you just go to activities, find the activity, and hit edit. I wish this feature was also available in the app but setting up Garmin connect on the computer for me was fairly painless.

Can you please explain more in detail, maybe same pics? For the love of God i can not find this option.

1) Go to this website https://connect.garmin.com/modern/daily-summary/2020-11-08/calories

2) Go to activities, all activities from the 3 bar drop down menu

3) click into your activity you want to edit

4) Click the gear icon and hit edit in the menu that pops out

Very confusing and not straight forward, please upvote so more can see  hope this helps!

Apologies if I've misunderstood something. I'm having issues getting my training plan activity top sync and so, in the end, gave up and did the workout. I would now like the workout to be classed as the part of the training plan but when when I edit there is no option. Or did you mean go to edit and export the .fit and then use fitfiletools.com to merge?

Why my 645 wont sync is beyond me, perhaps because I rescheduled for a day earlier as I initially had Mondays excluded from the training days.