Cable around headphone jack missing

I went to repair my daughter's 5C, (A1456), the dog knocked it into ice cream, then speaker to talk didn't work. Apple refused repair, said it had gotten wet. Then the digitizer broke. I ordered the digitizer and charging/mic cable. I am PC savvy, and can bake and Apple to get it working again, (BAD NVIDIA!) Upon taking it apart, I saw the small metal square, however not cable was attached to the headphone jack, (to take off old part and put on new. My only assumption is Apple broke it. What is it? Is it important? The antenna cable was in tact, everything else. Also, how to dig? prox sensor out for new LCD/Dig,cannot seem to see, is it paper and below the "thing" next to camera hole? AND the plastic bezel that goes around gasket for camera, doesn't want to stay on, do I just drop it into camera hole before adding the camera back in?

The part that the videos said should wrap around here