Did not do this, although I had read that the device should be turned off before doing the battery replacement.

Once you slide the pick (or plastic card) under the battery as shown, you can use the Opening Tool to pry the edge of the battery, It releases gradually, so be patient. Had to remove some tape holding down a cable running alongside the battery. Also needed to work the card between the battery bottom cover and the sticky tape. The battery connector unlatched easily, BUT:

Reversing the process to install the new battery is tricky because the new battery connector is very hard to align with its mate on the circuit board. You can’t see what you’re doing because the top of the connector blocks your view. You just have to guess about the correct alignment, and press down (used the back of the Opening Tool) until it seems to be mated. Wasn’t sure I succeeded until the case was back on, and I could try to turn the Voyage back on. BTW, all data was still there, though the new battery was only at 12%.

Case hard to slide off for me as well. Found that some double-sticky tape on the magnetic part overlapped the case and had to be carefully sliced. Was able to budge the case enough to give the opening tool purchase near the charge port, and pry that way. The case only needs to slide 1/2” or so and then it lifts off.

Definitely agree with this, and would clarify a bit. If the piece to be removed is at the top of the Kindle, the only purchase for the Opener Tool is the seam along the top edge. Start at either corner, and pry just enough to insert a pick, and repeat the process to work your way along the slanted edge towards the bottom edge; the adhesive releases easily. Continue along the bottom edge, then lift the bottom edge clear of its retainers. The whole piece can then easily be slid off.