Installing A-Pillar trim without busting it

I just repainted some A Pillar trim in my 68 Dart and when trying to reinstall, had no luck getting in place under the trim piece above the windows. Taking old ones out was easy because they were already broken but getting these new ones in is something I've never done and need some help with how to pull the window trim piece so I can slide the A pillar piece under it. Has anyone done this that can give me the step by step?