I don't measure everything and don't time, so it's just a method.
Light Roux - 1/2 cup flour, 1/2 cup vegetable oil, cook for a while
Add - 3 ribs diced celery, 1/2 large diced onion, cook until onion is translucent
Add - about 1 T minced garlic, cook a while longer
Add - 1 qt water, 2...