When it starts to boil, gather the foam, add an onion cut into medium pieces, the julienned pepper and 2 bay leaves.
If you have lean chicken (chicken breast), no fat, now add 2-3 tablespoons of sunflower oil to the soup - it's a tip learned from a lady I once hosted. It will give a perfect taste to the soup and will make it more aesthetic (you no longer have to fry the soup, the oil will boil and will have about the same effect).
Let the meat simmer slowly, over low heat - about 1 hour if it is tender and about 2 if it is country or other type (check that it is soft, and if you need to boil it).