So what is the first step? Lucky for you, it is something you probably do every day: walking. What is that you are saying? Walking is too hard on your joints? You are too heavy to walk? Well, you are in luck because you can walk in a filled swimming pool and get quite a bit of exercise in without destroying your delicate joints or feeling nearly as heavy as you might otherwise feel.
If you do not like walking, you can try other things, like lifting soup cans straight out to your sides and making little circles with them, ten at a time. You can even do exercises that use just the weight of your body, like trying this previous exercise without the cans. You can even work out while lying down. My favorite lying-down exercise for flattening stomachs is to just lie on your back and lift your feet off the ground and hold them a few inches off the ground.
Whatever you try, take it slowly. You cannot get anywhere if you burn yourself out right away. Start with a small amount of time. Maybe do some walking in place during commercial breaks at home. Then you can work your way up to five minute periods of exercise, then ten. All you really have to remember is that every little bit counts and that you do not have to do the exercise all at once for it to count as exercise.