How to start....I need to get started but I'm overwhelm......

You might want to head down to the Food & Nutrition thread and ask for food planners to contact you/friend you.

I'm not that kind of planner but we do pretty much rely on once-a-week shopping. I also do a lot of cooking sitting down because of a bad back. We don't have that many pre-made meals up in the freezer but I do have lots of portioned meats, many of them cooked. For example, when a 10-pound bag of fresh chicken leg quarters was on sale, I cooked them all at once and divided the meat into meal-sized portions for the freezer. Of course, I picked the chicken meat off the bone and packed it in the individual baggies sitting down!

Most of what we buy every week is fresh vegetables. All the cutting, slicing, chopping, etc. of them can be done sitting down. Same with grating cheese, assembling a veggie lasagna, making meat balls, etc. I do all of them sitting down.

Another thing I've taken to do so I don't have to stand at the stove and watch or stir is cooking in the oven or the microwave most of the time. If you search what you want to cook with the words "oven" or "bake" or "roast," you will find recipes online for all sorts of things you might think can only be done on top of the stove. After I learned how to cook rice in the oven I never looked back!

Even hamburgers can be done in the oven. Heat a cast iron pan in a 400F oven. Put the burger on the hot pan and shove it in the oven for 6-8 minutes a side, depending on how thick and how thoroughly cooked you want it. Want a brown roux? Bake the flour. The oven is your friend!