Can you post the recipe you are using? That will help in answering this question.
I’ve made soup using raw chicken and I’ve made soup using leftover cooked chicken. If you’re starting with water, gently simmer the chicken in the water until it is cooked through. Remove the meat, reserve the water (which is now broth), let the meat cool until you can handle it, then chop or shred it. Add whatever veggies/seasonings/rice/pasta you want to the broth, cook until those additives are done, then add the chicken just to heat it through. Voila, you have soup.
I’ve noticed when simmering raw chicken, you tend to get this foamy stuff on top of the liquid. Just skim it off.
If you’re starting with canned broth, you can still simmer the chicken in that to cook it. Or, you can cook the chicken some other way then add it to the broth. It really just depends on how complex your recipe is.
My lazy-ish soup recipe: Thaw out some frozen chicken broth (or you could use canned, low sodium fat free broth). Bring the broth to a boil, then add whatever pasta I have in the cabinet. Boil the pasta in the broth until it’s still a few minutes from being done. Add frozen mixed vegetables. Bring back to a boil until pasta is al dente. Add chopped leftover roast chicken. Simmer until heated through. Season to taste with salt, pepper, oregano, or whatever other herbs I find in my cluttered spice cabinet.
Sometimes instead of pasta, I use leftover rice. Sometimes instead of frozen mixed veggies, I use chopped up fresh carrots. The basic idea is to cook everything in the broth as you go. Soup like this is a good start, and then you can move up to starting with a whole chicken and some sauteed onions. My family loves my lazy soup as much as they love more complicated soups.
Whatever you do, it’s sure to be better than anything you buy in a can.