I'm not real familiar with that model, but I can give you some basics.
A) Remove the bioballs, if the bioballs are submerged, you might replace them with live rock rubble.
B) Add a light
C) Fill the sump as full as you can while still leaving room for power-out backflow.
D) Add either live rock rubble, cheato, and/or xenia to the submerged portions depending on your goals.