This repair will destroy your soul. I would not recommend even attempting it without even more specialized tools (eye loupe, headlamp, preternatural patience) as it is extraordinarily easy to ruin your phone with one quick misstep. I've thrown in the towel after weeks of attempting the job. After ripping the screen cable for the second and final time, I'm selling for parts.
This step doesn't give complete information.
The proximity sensor is adhered to the frame and must be loosened CAREFULLY and SEPARATELY before applying any pressure to the ribbon itself. It is extremely easy to tear the sensor from the ribbon, meaning when you're on a call with the phone next to your face, any touch will "press" an on-screen button. Look up images of these components to see exactly where they are placed and what they look like.