Wiring 3 way lights
3-wire cable from the fixture to the first switch. Between the switches you will need to run 3-wire (with ground) cable.
In the picture below, we show power coming into the light fixture. The black (hot) wire will pass right through going to the first switch. 
Attach it to the white wire of the wire running to the switch. The white wire from the power source will attach to the light’s white wire. The light’s black wire should be attached to the black wire running to the first switch.
At the switch the white wire coming from the light, will be connected to the dark colored screw.
Mark it with a black marker or paint the end black to indicate it is hot. The red and white wire of the 3 way lights going to the next switch should be attached to the light colored screws. Connect the black wire of the 3 wire cable to the black coming into the switch from the light.
At the second switch, attach the black wire to the dark screw and the white and red to the light colored screws.
