Loading your own training programme

I think it is currently possible only through the Training API | Garmin Connect Developer Program | Garmin Developers

Ah ok which is only for approved businesses I think. 

The only 'easy' option is to load the workouts into the Calendar.

I actually didn't know you could. I'll have to try to work that one out. 

There used to be a fellow who maintained a tool to use the API to upload training workouts.  It wasn't the most intuitive thing, you had to very specifically generate a spreadsheet with very specific coding but you could easily set up a handful of pretty complex workouts and then copy and paste them into other cells and then run a command to hit the REST API to put them on a user's calendar.  It honestly wasn't worth it for a single person but we had 3 people all doing the same training at the same time so it made it super simple to get everyone's calendars in sync. 

But alas he stopped supporting it and Garmin routinely updates the API which eventually broke it.  :( 

https://github.com/mgifos/quick-plan

If you're doing it for one person yes, you need access to the account then you go into training workouts, create the base workouts you want the target user to have then drag and drop them onto the persons calendar.   The next time the watch syncs they'll get them.   Note that due to limitations Garmin put into place around the time the 5X dropped they can only see 30 days worth on the watch even if you set up 30 years worth of workouts.   This also extends to integrating a user's calendar into a website or into another environment like Google calendaring.  Weird limit but is what it is. 

But if I load up a 16 week programme on the calender and don't care about seeing more than 30 days on the watch itself it doesn't matter then? Thanks for the heads up on the calender, after years of having fenixs I should have known that.