What are the instructions for making the Niçoise Salad?

Instructions:

1. First, boil the eggs, potatoes and green beans. Then, put them in the fridge until they are cold.
2. Next, wash the lettuce and tomatoes and cut the onion into small pieces.
3. After that, put the lettuce on a large plate with the tuna, tomatoes, onion, potatoes, beans and olives.
4. Finally, make a dressing with olive oil, vinegar and mustard. Put it on the salad and mix everything together.