3.Align the connector with the socket so that the row in the connector with the blocked hole lines up with the row in the socket with the missing pin, as shown below.
Make sure the holes fit over all the pins and then push in the
Connector.
4.Locate one of the power supply cables that lead from the power supply (behind the horizontal drive bays). The cables are labelled P1, P2, and P3; you can use any one.