When I make chicken soup I use stock made from my previous collection of bones.
Add veggies, herbs & spices I'm in the mood for and have on hand.
As stated earlier it's best to start small and add later. You can always put more in but it's hard to take it out.
Simmer until the veggies are getting close to done tasting as it progresses and adjusting the seasoning.
Add the chicken. I usually use cubed thighs but whatever you have will work.
Keep cooking and adjusting until the veggies and chicken are done.
I see making stock/broth as a separate entity from making soup.
To make the stock/broth the ingredients are cooked to much to extract flavor to make them usable in the soup.