Easy one first: ground wire to green screw. We have to assume the two black wires are the hot(coming from power source) and switch leg(going to light). Switch will have two brass colored screws. Looking at the switch with the off/on markings right side up. Put hot wire on upper screw and switch leg on other brass screw, With nothing hooked up, the hot wire will be the only wire with voltage on it. You can buy a non-contact voltage tester at Lowes or any place that sells electrical supplies. Now we must assume the two white wires are neutrals(one coming from power source and one going to light. The pilot light part of the switch will either have a silver colored screw or a white pigtail on it. all whites hook together. The pilot light is wired internally to the switch leg. Your switch should work properly now.