Can you tell me how to cook a real carbonara sauce? Please give me also the quantities of the needed ingredients for 3 persons. Which kind of pasta should I use?
Sure, here's a recipe for authentic carbonara sauce for 3 people:

Ingredients:
- 300g spaghetti
- 150g pancetta or guanciale (cured pork belly or jowl)
- 3 large eggs
- 75g grated pecorino romano cheese
- 50g grated parmesan cheese
- 3 cloves of garlic (optional)
- Salt and pepper to taste

Instructions:
1. Begin by boiling a large pot of salted water for the pasta.
2. While the water is boiling, cut the pancetta or guanciale into small pieces and set aside. If you prefer, you can also chop the garlic cloves and add them to the pan with the pancetta.
3. In a large mixing bowl, whisk together the eggs, pecorino romano cheese, and parmesan cheese until well combined. Set aside.
4. Once the water comes to a boil, add the spaghetti and cook according to package instructions, usually around 8-10 minutes or until al dente.
5. In a large frying pan, cook the pancetta or guanciale over medium heat until it is crispy and the fat has rendered, about 5-7 minutes. If you added garlic, cook it until fragrant and lightly browned, about 1-2 minutes.
6. Remove the frying pan from heat and use tongs to transfer the spaghetti directly from the pot to the frying pan. Make sure to reserve a cup of the pasta water.
7. Toss the spaghetti with the pancetta or guanciale and the rendered fat until well coated.
8. Pour the egg and cheese mixture over the pasta and quickly stir until the sauce has thickened and coated the spaghetti evenly. If the sauce is too thick, use a little bit of the reserved pasta water to thin it out.
9. Season with salt and pepper to taste.
10. Serve hot, garnished with additional grated cheese and black pepper if desired.

As for the type of pasta to use, traditionally spaghetti is used in carbonara sauce, but you can also use other long, thin pasta like linguine or bucatini if you prefer.
How much salt should I place in the water for step 1?
Based on my analysis, the suggested salt amount when cooking real carbonara sauce would range from 1/2 teaspoon to 1 teaspoon per serving.

However, it is important to note that the exact amount of salt will depend on personal preference and other flavorings used in the recipe.

It is recommended to start with a smaller amount of salt and adjust accordingly to achieve the desired taste.