Conclusion:

“To reassemble your device, follow these instructions in reverse order. “

Something goes wrong here…

Maybe you released/loosened its connector or you damaged the board?

I think this is not very difficult, mostly you can simply pull off the plastic frame that is over your LCD (be carefull with pulling off!). You can pull it off with your fingers starting inside.

(Plastic frame can damage, but they are not expensive).

Then remove some screws, LCD will release, but it is still connected with some cables on the backside.

Try it and make pictures, so you can create a guide :).