The lens has strong magnets in it that will attract the screw unless you're using a magnetic screwdriver of the exact right size. I also had to tape the back of the lens to the table so it didn't move, as well as tape the bracket in the right place.

Yeah, it's a T6, not T7.

For the smaller two cables, push the brown plastic piece away from the white piece to release. For the bigger cable, the brown piece is on a small hinge and you need to rotate it towards the white piece to release.

You first have to detach the foam on the front in order to take the cover off because the foam is gluing the two halves together. Just slide a spudger underneath it along the bottom and sides, making sure you're actually going underneath it and not tearing it.