I have made seafood paella where I cooked the scallops directly in the rice, but I do not prefer this way. I find that you do not bring out the best flavors in the food this way. I prefer to sear the scallops on their own.
Paella Ingredients: Homemade vegetable broth (celery, yellow onion, parsley, bay leaf, a little garlic, EVOO, salt, pepper), saffron, special paella rice, diced shallots, sauté these in a pan on medium/high with olive oil (not EVOO since it will not cope well with the high heat!), add in orange and yellow pepper, add in one can of high quality tomatoes, add in minced garlic, add in jalapenos, add in 1.5 cups of rice. Allow rice to soak up some of the mixture, then add in vegetable broth. The broth should just barely cover the grains of rice. Add in cilantro at the end.
Scallops: Fresh scallops (clean and then allow to dry by keeping them lightly covered in the fridge), add salt and pepper, lightly coat them with avocado oil.