Extension of headlights at the front

Hi, guys.
I have a problem and this is what
How do I build the headlights at the front? I want to be

1. the chrome ring in front of the reflector is black so that only the reflectors are blank.
2. wash out the headlight glasses inside because the inside are full of dirt.

I've been looking at this for a while, but no idea how it works.
The two screws on top is clear but how can I get to the bottom,
can not be that the bumper has to be disassembled, can it?

Thank you for every answer
Greetings Björn S.