Place chicken in large gumbo/stock pot, fill with water just to cover chicken well, boil til done. While chicken is cooking, cut up sausage into rounds, then cut rounds into quarters. Brown sausage in a skillet, drain on paper towels. Chop garlic, onions and celery and brown in the sausage grease. Remove chicken, cut up into small pieces. Dissolve bouillon in chicken broth. Add soup to broth, continue to simmer, add more water as needed. Add garlic, onions and celery to broth. If using okra, add now. Add seasonings to taste to broth. If desired, you can add diced tomatoes (like ro-tel). Add chopped chicken and sausage to mix. Continue to simmer, covered.
Now to make the roux: This is like making gravy - use remaining sausage drippings, add oil and heat in skillet. Sprinkle flour into oil, stirring constantly, until all added and mixed well. You may have to add more flour to get the right consistency, should spread slowly back out into pan when stirring/scraping the mixture. Stir constantly, do not let it burn. Cook until it is the color of dark peanut butter. Remove from heat. Slowly scrape the roux mixture into the slowly boiling gumbo mixture, stirring as you add it, and scraping the bottom of the gumbo pot for roux that settled to the bottom. BE CAREFUL as it will steam up quite a bit. Stir constantly until all roux thoroughly dissolved into gumbo. Let simmer for 30 min to an hour, stirring occasionally.
Serve over cooked white rice. I like Jasmine rice.