Turn signal switch help

Hello
I am rewiring the Dart in my spare time. I got the engine running two weeks ago, since then I have been away on business.
Today I installed the autometer gages crank it up and the voltmeter showed a steady 14 volts.
My question is the turn signal switch connector, has two green wires for the left front signal, and there are two tan wires for the right front.
I am trying to learn why there are two wires?
If you look at the photo there is a white wire with a connector, is that the one that connects to the brake light switch?

Also I had to install new sockets for the rear lights. I bought some sockets tht snap into a 3/4 inch hole. There is no ground wire, how are these grounded? The housing that they snap into is not metal.

Manny thanks
George G

SANY1437.jpg

SANY1438.jpg

SANY1439.jpg

SANY1440.jpg

SANY1441.jpg

SANY1442.jpg