Insert screws from the front of the panel and through the fan. Then loosely attach the nuts.
Note that there are only two screws and they have should go in the specific position shown. Adding screws to the other positions may risk touch and shorting out the control board.
Note the orientation of the fan (label side towards the circuit board) as this is critical to push air in the right direction. I initially installed the fan the wrong way, pay attention to the third photo for the correct orientation.
After confirming the fan orientation and screw position, use the 2.5mm hex key and a socket or pliers to snug the screw and nuts. Don't over tighten. If you would like to add Loctite, now is the time.
Gather and Assemble the back panel
Back Plate (1x) A Level Foam
M3 x 12mm Socket Cap Screw (2x) Bag C-10
M3 Nut (2x) Bag C-10
Pre-wired Power Outlet Assembly (1x) C Level Foam
2.5mm hex key, 5.5mm socket or pliers, and Loctite Low Strength (optional)
Thread the wires of the pre-wired power outlet into the back plate starting from the front.
Attach the M3 Nuts and tighten. Use the 2.5mm hex key and 5.5mm socket to tighten the screw/nut combo.