Just grab a friend and an ohm meter. Six bits the green is the ground but it's easy to test with a meter. Once you find that, have your bud step on the brake and you're meter will show you the hot wire.
Just for the negative naysayers here, you slip the plastic tube over the Fumoto, run the tube into your container, and flip the lever. You don't need to wear plastic gloves because there's no mess.
For those of you who change your oil, they're slick.