Especially my knees and legs were so infirm, I could not trust them. If I had a chance to walk a bit faster for just a couple of meters, I never did it, preferring to wait for the proper traffic lights! Now I cross the street running, even if I have only a risky chance! But now I do some exercise every day, and I am also in my normal weight. I'm not an athletic type, otherwise I wouldn't have become fat, I guess. By exercising I don't mean (and I didn't need) anything exhaustive or excessive!
Exercise bores me, I must confess, and I never followed a method in a gym or at home. What I did was to just stop watching my favorite movies sitting in the sofa! I combine movie time with exercise, using a stepper. You could use a bike, a treadmill or anything similar. Once in a while I stop ‘walking' and continue with weights (still watching my movie). I started from a 3 kg unit in the first weeks. When that became easy, I went to 5 and now I am and most probably I will remain to 7 kg (about 15 lb.).
If you enjoy a better physical condition you can use two units. I preferred just one to prolong my exercise by changing hand. Using two units you find both hands simultaneously tired, which leaves you waiting until you are able to go on. Note that light lifting, such as vinyl dumbbells, is aerobic exercise; it allows and needs many repetitions or ‘sets', as they are called, that make you breath more intensely for more time. Don't confuse this type of exercise with heavy lifting, where athletes are trained to handle the heaviest possible weight just once.
Any exercise is great, even a simple walk outside. If you feel bored, just use those earphones to listen to your favorite music. As you lose weight, day by day, exercise helps not only by burning calories and giving strength but also because it lets you feel intensely your body getting better. Exercise creates conditions that contribute to your confidence. Just make sure to use this confidence to fulfil your goal and not to postpone it! Here is the amount of calories you can burn in some activities.