1967 MG Midget head lamps

First you have to know if it's positive ground or negative ground. The ground wire should go to the center spade sticking out from the headlamp. The left one if you put power to it will or should be the low beam. The right one should be the high beam. If you plan on keeping this car I would highly reccomend getting teh book by rick astley on mg electrical systems. It goes through everything there.