The NF-A6x25 is a 4 wire PWM fan. Since we don't need all 4 wires cut the harness to length(12" should be enough).

Crimp on some JST 2.54 connectors.

4 Pin fan: Yellow is 12v and Black is Ground

3 Pin fan: Red is 12v and Black is ground

Mount the NF-A6x25 were the original fan was with the 2 screws that held in the Sunon fan. Make sure the airflow arrows point towards the board.

Insert the board into the case and secure it with the 5 screws.

Connect the NF-A6x25 fan to the board. Positive on the left and Negative on the right

Slide the casing cover on and the remaining 6 screws