If only it were simple enough to sum up in one post.
It took me months of researching to learn all I have about dog food, what the ingredients were, what was good & what was bad. So trying to sum it up is pretty much impossible.
My advice is to start searching.......there's a ton of info on the internet about the ingredients in dog food & comparison of different brands of dog food.
I sure wish I could help you......perhaps somebody else might have some other ideas but the only thing I can suggest is to do research & a lot of it. That's how I learned & actually wish I could go back to those days when I opened a bag of food & threw it in my dog's bowl. Those days are long gone!