Locate the Power LED cable attached to the case. If the Power LED cable
has a 3-pin adapter, you must use the 2-pin to 3-pin adapter which comes
with the packaging.
The heads of the power cables usually have a triangular mark which
indicates the positive electrode(+). Connect the 3-pin end of the adapter to
the Power LED cable, matching up the positive electrodes(+).
Finally, attach the 2-pin end of the adapter to the ACPI pins on the
mainboard, making sure you match up the positive electrodes(+).