Gotcha covered Martha...this isnt 100% "authentic" but its good and easy. This recipe is for a lot, as I make it on football sundays, adjust as needed. Leave out or substitute any of the meat/seafood as needed to suit tastes...
Make the roux - this is the most important part. You can make this roux in bulk and freeze it if you want more spontaneous gumbo.
Saute 4-6 slices of bacon or bacon chunks or meaty salt pork or whatever have you along with a pound or two of andouille or other firm spicy sausage. Take out the bacon and sausage and leave the fat. Add one large chopped onion and cook until the onion is starting to become translucent, then lower heat and add 4 chopped cloves of garlic and stir occasionally for 5-10 minutes until browning starts. Remove onion and garlic and leave the drippings.
Add 1 1/2 cups flour slowly while stirring. If you dont have enough bacon fat left to make a paste, add butter until you do. Cook slowly, stirring often over low heat for up to 40 minutes until you have a nice dark brown roux. Color of beef gravy is about right. Put the bacon, sausage and garlic/onion mix back in to the roux and reheat.
While the roux is getting brown, in a large pot, boil 2 cups of water. Add salt to taste (teaspoon or two), 1/3 tsp crab boil seasoning (or to taste), 1/2 tsp thyme and a teaspoon of whole peppercorns. Add 1 1/2 lb chicken and long cooking seafood (uncooked crab, etc) and simmer over low heat for 20 minutes or until done. Add a cup of sliced okra and a 16 oz can of diced tomatoes to the pot.
Add a quarter to a half cup of the hot water from the pot to the roux slowly while stirring to loosen the roux. Scrape all of that back into the big pot with the water and chicken/crab and stir well.
Add 2lbs large cleaned shrimp and simmer until shrimp are almost done. Add a pint of raw oysters and simmer for just a minute or two.
Serve over rice.