Additionally, be careful cleaning out the battery holes using a pin. It’s easy to tear the conductor so you have nothing to solder to. I was able recover from the one I messed up by soldering to the other side of the board which was still intact. It looked OK but I don’t know if it worked as I wrecked the device on reassembly as above

This is a difficult repair. Ref jandrews33 comment on 1 May above, there is a lip of plastic running across the device just below the window (maybe a part of the screen moulding?). It protrudes into the centre of the case and can catch on components as you slide in the logic board and screen assembly. This is problematic if the replacement battery is even slightly thicker than the one you remove. Mine was. Like jandrews33 recommend using a very thin sheet of plastic to assist inserting the board and screen without anything catching. The sheet needs to be tough so you can pull it out again after assembly. It will also help the black foam rubber screen surround slide into the case. The surround can be a bit sticky otherwise. The orange plastic circuit sheet below the display caught on that lip and ripped so device is scrap now.