When putting back on, run a pick along the edge of the shield between the wires to make sure nothing is pinching and the wires are clear of the shield before screwing down.

It's not super clear from the pictures but you're aiming to remove the black strip, not just the small white square sticker. Use heat and go slowly.

When putting the fan back, it's easier to plug the fan in first before screwing it in place.

Use some heat here from a hairdryer to make this part easier.

If you screw up here you can replace the little aluminium square with some aluminium tape from Amazon. No less than 50 microns thick, slightly thicker is fine. and the square is 13mm both ways.