The case is supplied with one or two 3-pin fans, and has a three-position fan speed manual control switch on the rear right above the rear fan position. I expect there are four cables in that area:
(a) one ends in a wide connector that must plug into a SATA power output from the PSU to supply power for the fans;
(b) one ends in a female (with holes) 3-pin fan connector coming from the fan, and it must plug into one of the switch outputs to power that rear fan; and,
(c) two are male 3-pin fan connectors as outputs from the switch to supply two fans.