During reassembly, note the following:

Make sure all 17 cables are above the logic board as you place it in the frame.

Use the point of your spudger to pull cables out from under the logic board if they slip underneath.

Hold the rubber spacers out of the way so the fins can drop into their recesses.

Align the heatsink by sliding the heatsink fins between the rubber spacers on each side of the MacBook.