Clean the mussels or the clams, you can find instructions on how to clean fresh mussels on my website.
Heat 30 ml olive oil in a frying pan, fry 3 cloves of chopped garlic and add the mussels in. Stir well, put the lid on and cook for 3-4 minutes, shaking the pan frequently. When most of the mussels have opened, turn heat off.