My suggestions for installation:
Get two M3x15 screws.
Mark or note the flat cable orientations!
Disassemble as described.
Remove flat cable from both sides.
Put everything together including the box behind the display, but do not yet install the display.
Use the two additional screws to mount the display frame.
Once completed plug the flat cable into the display and slide it in the frame.
Lastly feed the flat cable through the opening and plug into the motherboard.
Done much easier.