The MOLEX connector should be split so there should be a couple of connectors coming from both. The 3-pin should be connected to your motherboard's SYS_FAN1 connector.
Many thanks g unit, I'm going to try it now,
Sorry for asking this last question, but I'm not very confortable doing this, first time build
, should I leave the molex just hanging, and not connected to anything?
Again many many thanks for the help !