Disconnect the 2 ribbon cables from the main board (Red boxes)

Lift the black tabs above the cables to release the cables

When reseating the cables, make sure they are fully seated before closing the locking tab

Note: there is another ribbon cable under the left one which goes to the 10-pin accessory port, make sure it's seated correctly when reassembling.

Disconnect the wifi sub-board with the wifi cable from the main board (Blue Box) or gently disconnect the wifi antenna (Blue circle)

The antenna connector is very delicate, and isn't designed for many cycles, which is why the board is recommended (it has a socket it fits into.