When I met my now-husband, he had 2 kids, so suddenly I was thrust into the "weekend cooking but make it kid-friendly" world.
I started with a basic "cooking for 1 or 2" cookbook for college kids - and doubled everything. Most were 5 ingredients or less and didn't require a lot of fancy equipment.
Now there are "5 ingredients or less" books with pictures, and 30 minute meals. Try Rachael Ray to start. You can also look at Jessica Seinfeld's 2 books on healthy food for kids - also simple to do. If I were you, I'd go to the library and look for a few of those, borrow them, and try a few things before committing to purchasing a cookbook. Get one of those book racks at your local bookstore so you can prop the book up - and start with one with a lot of photos. Don't be embarrassed to look for a book that defines terms and explains what different methods are used for.
I agree that All Recipes and all those sites have great recipes - but it's hard to search for things and then prop the computer up in the kitchen (LOL) or print out a bunch of things you don't even know if you like yet. Once you get this down to a science, you can start a binder or recipes you either printed out or pulled out of a magazine.
Decide what equipment you want to use too. If you're cooking for a big family and you're at work all day, you'll look at a crockpot and casserole dishes, if people like those things (soups, stews, casseroles). If you want chicken & rice & a veggie (3 separate foods rather than a stew), you want a baking sheet, sauce pan and a smaller pan with a veggie steamer. So before you invest in a lot of equipment, start with what you have.
Remember also that a lot of vegetables are available in the frozen section - you don't have to start with a lot of chopping and peeling if you don't feel confident. They don't work for everything, but they do for many. And they are much, much better than canned vegetables and often have more nutrients than fresh foods that have sat in the store or in a warehouse for a while.
If you can bake, you might look at things like quiches and frittatas, which are basically mixing ingredients, pouring them into a pie pan, and putting them in the oven. You might also look at the local Y or community center to see if they have mini-courses.
Look for tutorials on youtube also - watching someone do it makes all the difference. And you can stop the video while you duplicate the first steps, then start it up again.
Good hints are to get all your ingredients ready and even measured out into little bowls or whatever, before you start. Look at the item that takes the longest, and start with that. While it's cooking/roasting, do the next thing. For example, I start the brown rice which takes 45 minutes, then start frying up a little hamburger meat or chicken strips, then making enchiladas with tortillas, drained canned beans, some frozen peas or corn (don't even defrost them - the oven will), some diced green peppers, and some grated cheese. That takes 20-25 minutes, and the finished enchiladas go in the oven to finish at the exact same time as the rice. Do that for everything else you make.
Feel free to message me with preferences for what you think people like and what your cooking schedule is (make ahead, whip up after work, etc.) and any allergies. I'll send you a few things you can try.
Good for you for trying to master a new skill! I did!