Start with the level I programs, even if only at level 1 (3 sets), Vitality being a great one. Take in the habit, day after day after day. After a few programs you'll be able to add more sets, then level II programs... Your body's been through a lot, so it takes time, but it is possible. Hugs of encouragement!
In my own case, I had 5 hospital stays (including a 6 week one), one major surgery (open heart surgery), and another minor surgery in 20 months. The level I and II programs were really the key to get me back into shape. Hoping you find here the support and encouragement to start and stick to it, don't hesitate to make a blog! It helps!