I reassembled my phone, but the device wasn't closed tight enough, so the screen, on either bottom side part (above the power button), was protruding about 1.5mm up. I ended up just making sure that those slots on the back cover were installed correctly. And then I made sure the bulging side got in first. The rest I literally just pushed hard in and it worked! I also ensured that the top part went in first because it has all those grooves.