The black wire is the power and the white is the conmon or neutral and the green is the ground wire.Black wire to the switch from the switch to the black wire of the light.The white wire to the white wire and the green wire to the metal houseing of the light.The green wire is very importion,it is the ground.Just in case the light shorts out it will pop the breaker and not shock
the hell out of you or kill you. Hopes this helps.
P.S. this wiring in the usa 120 voit ac
Peace and HAPPY TURKEY DAY :rasta: :thumbsup: