Now – as mentioned before – cut the M3 threads into the blind holes.
After cutting the threads, make sure to shake out a the chips.
Insert the mainboard. (the amber ribbon cable goes thru the slot)
Screw in the the two screws located next to the slot in the pcb. (The other two screw holes are our M3-threaded hole, leave them blank for now)
Re-insert the amber ribbon cable. For that: first pull up the brown plastic part on both sides of the jack. Then insert the cable and pull the brown plastic-part on both sides down
Re-insert both white ribbon cables. (tricky)