Screen Replacement Not Working

I replaced a screen on an iPhone 12 Pro. I tested the screen before removing the camera from the original. The test involved plugging the phone in and seeing the battery charging on the screen because the battery was dead. I went ahead and finished the replacement procedure. Before pressing the new screen onto the new glue I tried another test and nothing came up on the screen. I am at a lost as to why the new screen doesn't work now.