Lay down and pretend your riding a bike. Just move your legs in that motion and it'll work out your legs. Crunches, sit-ups, push-ups, and weight lifting will help with legs and tummy :) running while holding 5 pound weights helps too! I hope this helps!!
It takes awhile but doing push ups and pull ups and curl up help your stomach. Lifting weights and eating good help your arms and mussel. Head to a gym sometime, maybe get a trainer if you can. Or do some simple workouts.