Why can't my Display turn on after I replaced the battery?

I followed the Ifixit directions to taking out the battery and replaced the battery with the one that Ifixit sent me. Everything fitted back in right. I needed to test the Display to make sure the cell phone is back up and working, but after two minutes of fighting to connect the Display back into it's connector, the Display would not turn back on. I can hear the cell phone turning on but I get nothing on my screen. I've taken the Display off the phone four times and checked each connecting part as well, but they look fine, I would put it back on and still got nothing on the screen. I don't have another Google Pixcell 7 Pro cell phone to test the Display or the connection. What can I do next?