? connecting wires for halogen lamp with hi.low/off?

How do I connect wires with a toggle switch for hi/off/low? 2 Black wires coming in from regular power source. Switch has a black covered wire with an exposed wire out the side and back to the switch base. It also has an attached green wire on the other side. Two white wires lead up the lamp stem to the halogen bulb. Need help with how to connect.