If you're using frozen seafood, place the bag with the frozen seafood in a large bowl filled with room-temperature/lukewarm water. Place the seafood in the water when you start cooking.
saute the vegetables and rice
Place a large non-stick pan over low heat. Add olive oil, finely diced onion, finely minced garlic, and finely diced celery. Cook for 5 - 8 minutes, stirring occasionally. Add the rice, stir and cook saute for 2 - 3 minutes over low heat. Increase the heat, pour in the white wine, and cook for 1 - 2 minutes, occasionally stirring for the alcohol to evaporate.
cook the rice
Gradually, ladle by ladle, start adding the vegetable (or fish) stock. Add the next ladle of stock only when the first one is cooked into the rice. Repeat the process until the rice almost cooks. It will take about 12 minutes. Make sure to stir the risotto regularly.
add the seafood
Add the seafood to the risotto and bring to a boil. Simmer for 5 minutes cover with a lid. Remove from the heat, add in the butter, stir for the butter to melt, then season to taste with salt and pepper. Cover with a lid and set aside for 2 - 3 minutes.