I started by using boxes of mix and following their instructions, then trying to recreate the mix myself. For example, one of my favorite meals growing up: Chili Macaroni Hamburger Helper. It's mix, macaroni, and then you add milk and hamburger and simmer it. Just following box instructions is enough for now if you're truly starting from zero knowledge, because you'll build confidence measuring, setting heat, monitoring, cracking eggs, checking cooking temps, chopping stuff, and so on, the absolute basics of the basics.

Last night I made a stew which is basically the same thing, except I chopped the chilis and other veggies myself to substitute for the mix, and I used TVP to substitute for the hamburger (you could also use beans for this purpose, or both), turning it into a from-scratch vegan alternative. It doesn't taste the same so I wouldn't call it a "replacement", but everything is subbed in for something similar enough so that the end result is well balanced in the same way that the original recipe is.

Food 'aint rocket science, and people have been making it purely on instinct for thousands of years. Granted, your instincts aren't perfect and you're gonna make mistakes, but your instincts are probably a lot better than you think they are and you can probably make more things than you "know" how to make just by putting the ingredients in a pot or pan with medium heat and sending it. Specific things like pressing tofu or safe cooking times you'll still want to look up, but I think getting into the "experimental mindset" is the most important thing of all.