How do I attach wires to this socket
I believe that the red arrows are pointing at the tabs that actuate the spring clips in the holes on either side of them.
Depress the spring clips  by inserting a small flat blade screwdriver into the opening and press down,  then insert wire into hole, release spring clip and the tension should keep the wires snug.
I believe that there a two holes on each side so you can send another set of wires out to daisy chain  another fixture.