Do you cook them the same as crawdad's.
Pretty much. Your seasoning goes into the water, you let it come to a boil, add your seafood, let it come to a rolling boil and cook appropriately, then let them soak in the flavor. For crabs I like to boil them around eight minutes and let them soak for about twenty.
The other stuff like onion, garlic, sausage, corn, potatoes... should be cooked separately with a light soaking or it will retain a lot of spice!