What's the (installation) Trick?: Headlamp Bezel/Trim Ring

I'll try again. I clip it on the bottom, but when inserting the two top screws it pops off again.

Stupid question but make sure it's not popping off because the holes you're screwing into are stripped out.
Mine were, previous owner used hillbilly wood screws to hold the trim ring in.

Hope you have some good luck.