For reinserting the logic board, it helps to have a second person helping hold connection points to the side so you do not accidentally lay the logic board on top. Just go slowly, being mindful of all connections. (best to start by properly seating the DC power unit in the upper right corner)

For reinserting, just be patient, lining up the ribbon, keeping a good hold on the tab, and applying even pressure along the ribbon, slowly, firmly reinserting. If the power button doesn’t work when you put everything back together, you will know the ribbon needs better connection. I promise you can do it!

power connections for the fan connect vertically into the logic board, rather than being pulled parallel to the board. Inserting spudger and rotating underneath the wires helps the connect pop up.