Start on the oliptical, run on it for 20 min, every couple min throw a good fast pace for a 30 40 sec or more. try and do it 4days a week. when you start to build stamina throw in some treamill runs, eventually all your running needs to be outside. try and set a goal like by the end of this you can do 5 to 10 miles in 1 hour. I started at 225 or 230 lbs, in a 4 to 5 month period i lost 30 lbs and was runing 10 miles in one hour give or take a mile.