I have a few recipes I use that I love. Simple, cheap and work better than anything I can buy. Sometimes these very necessary things can be overlooked and shouldn't be in a SHTF situation.
START, start now, you will fail many times. I say this from experience. Growing up in the city I had zero experience growing a garden. Spent some money got a truck of dirt planted a bunch of stuff and grew a mountain of weeds lol. Failure is part of the process. I am happy to say that after a few years of effort I can grow a few things. Buying a bunch of seeds and having a plan is not growing food, that is only a dream. Get dirty and practice you will have success and failure but you will learn. YouTube is a great source for anything you are trying to grow. Look for a grower in your grow zone. MIgardner is a great source for upper Midwest info. Deep south homestead is great if your down south near the coast. There are many great sources on youtube, use them practice and learn. Make notes on everything you plant and when you plant it. I was amazed to find out that I could grow a great crop of onions, garlic and carrots over the winter. Good luck and plz just start do something if you wait till you have to feed your family it may be to late to learn.