Reassembling it is not simply a matter of following the reverse of the disassembly instructions. You need to clean off all the adhesive tape pieces and residue. That is by far the most time consuming and potentially damaging part of this job. The adhesive will be very difficult to get off in some places. I use a combination of blow dryer with low heat, the pointed end if the plastic prying stick to rub it off, chiseled cut pieces of pencil eraser sticks, to rub it down even more, then finally, and very, very carefully, alcohol to get the residue off. Just wet enough on cotton cloth and cotton swabs to wipe but not to have it seep into delicate areas! Rub along and outboard of the edge of the display only to avoid damaging edge. It you don’t remove all the tape pieces and residue and have a clean and level result for the new tape then the display will not only not sit flush like a new iPad but it will not stick well!
Cellular model users see my important comment about thecelluar model in the beginning of the guide!
The only tape adhesive kit that iFixit sells is incomplete for the cellular model. The are five extra small pieces of tape that go inboard around the cellular antenna. You will need to request another tape kit from iFixit, like I recently did, to cut custom pieces for that section. Amazingly I got pushback on that and was told that their kit is correct for the cellular model too, even after showing clear and obvious closeup photos of the leftover adhesive in those sections. That’s inexcusable for a repair site!
Use blow dryer on low instead. Much easier and much faster.
What you need to do is move the display inboard up to the edge area of battery! That will relieve all the stress on the cables. Simply holding it straight up is not enough, especially later when you go back to reconnect the cables and the bracket over the connectors.
I also used a hairdryer. I used it on the low setting and I cut a piece of carboard to protect the rest of the screen. The iFixit tool and method is vert tedious and very time consuming in comparison. With the hairdryer method you can literally have the display apart in a few minutes. Using your other hand nearby the area you are heating it should be very hot but not enough to burn your hand. You only have to heat metal part of case near glass edge. If you have a cellular model then you need to be very careful because the black antenna area is plastic. So less heat and work your way up in adding heat just enough to separate around the area but not so much you melt the plastic!