Most motherboards come with two rgb headers each supplying 12v of power.
Connect multiple fans to motherboard.
This wire can either be plugged into a normal fan header on your motherboard or preferably into a corsair commander pro.
Such a splitter connects two or more fans to a single fan header on the motherboard.
Finally you can do molex straight to the fan which i don t have much experience with but iirc you need a hardware volt adapter small cable thing to avoid running at full speed at all times.
The cabled labled to rgb hub will plug into the small 6 port corsair rgb fan led hub that comes with the multi pack of fans.
The last pin just won t be used.
However if you have a particularly large pc case that you plan on filling with multiple rgb fans each requiring its own.
Well that depends if that fan splitters have 4 pins that means its pwm which the fan speed ia controllable you can use 4 pin splitters in 3 pin applications.
In fact there are a number of ways to do so.