The Momentum fans included with the Meshify 3 XL have cabling with proprietary connectors specifically designed for the Adjust Pro Hub. Therefore, there are two separate methods for installing fans depending on if you have the RGB version or non-RGB version.
RGB-version
Chain the fans together (there is a female and male connector on each fan cable) and connect to the extender cable from the accessory kit:
Connect the extender cable and the other cables to the Adjust Pro Hub:
Take the PWM-cable from the Adjust Pro Hub and connect to a 4-pin PWM header on the motherboard.
The USB-cable coming from the Adjust Pro hub should be installed on a USB2-header on your motherboard.
Location of these may vary. Refer to your motherboard manual for the specific location on your board.
Non-RGB version
Connect the included Legacy-cable to your fans:
After, connect this cable to the included fan hub on the backside of the motherboard plate (right side of case in the top).
The cable coming from the fan hub is then connected to a 4-pin PWM header on your motherboard: