[Misti1980]

How do I get the black hard plastic off to install this part? Tya!

 

[Blvckhvrt]

What part are you trying to install? If it's just bulbs, those gray plugs connected to the metallic sections with the green and whitish wires coming out of then just pop out and take the bulbs with them. Or if you mean you're trying to replace the whole some light, use a plastic spudger and stick it between the edges and it should unclip and pop right out.