what's the trick?

As you can see its coming, but nothing is cooperating very well, every time I go to do something there is an issue (kinda like life sometime) Who knows the trick to snapping these drip edge covers back on? I think I can deal with the extra mills of paint (as you might be able to see some has chipped off already trying to get them on), the curved one goes on last doesn't it ? and what end is easiest to start with on that piece ?