I have the D201GLY2A (same board as your's, but with different heatsinks and a CPU fan). next to the RAM stick there should be 2 SATA port and 1 PATA (IDE) port. your HDD plugs in the one of those ports.
then connect power from the opus. (you may need a PATA>SATA molex adapter if your HDD is SATA).
