Garmin 520 outside workouts

I want to do a long outside ride mostly unstructured but with a 1-1.5 hr outside TR workout in it using a power meter and Garmin 520. How do I start the ride and then into the ride start my workout. Then finish my workout and then finish my ride. But then retain all the data?

Just pick a + or - version to fit your needs

Usually the second warmup interval will be free of a time restriction, allowing you to cycle as much as you want before starting the workout proper.

When doing the outside workouts, is there any way to turn off the on screen warning that im above target power? Would this be a TR app adjustment or a Garmin 520 adjustment?

Garmin 520. Tucked away somewhere in your profile settings you’ll be able to turn them off.