I started out with walking too. The only equipment I was able to use was my rowing machine and I used only the arm part (rowers). I had almost every piece of equipment you could think of -- treadmill, stationary bike with moving arms, rowing machine, a recumbant bike with moving arms, and some other pieces. I donated all of them but the rowing machine to a charity second-hand store that sells them and uses the proceeds for their food bank.
Then to the walking, I added in hand weights, dancing, arm and chair aerobics, and this has helped me get more fit. I second that how you are eating is the most important thing to watch -- eat half your plate veggies and salad, with lean protein and a small amount of veggie or whole grain carbs (i.e. new potato, sweet potato, or corn; or beans, brown rice, barley, wg pasta, etc). In the beginning, I used to have at least two veggies AND a salad to fill me up; now I eat a bit less, but I often have a salad before my dinner still. Snack on fruit first and yogurt is good too. In time, you will find what foods work for you to fill you up -- soup and salads really help me a lot.
This is a very busy time of year and some of our regulars only come in 1-2 times a week; many work so come in on the weekends; and I am far away from home waiting for surgery on Monday am. Eventually, some of our regulars will come and answer you. Best of luck with your plan ...