I'm not sure what your specific goals are, but it all starts with doing a small amount of activity every day. You'll quickly be proud of yourself for it and increase the workload on your own. Try something simple like some standing squats, lunges or calf raises. No weights needed and you can do this anywhere. It all starts with doing the first rep or set. Once you get in a rhythm, you'll feel better. Effort equals results, so you just have to start challenging your body and it will respond.