How to make
Grate or puree the tomatoes and remove seeds if you like. Cut the garlic into slices.
Heat the olive oil over medium to high heat and fry the shrimp - whole, until they change their color (for about a minute).
Take them out and add the mussels and clams. As soon as they open up, which happens almost immediately, take them out as well.
In the same fat, put the garlic, by reducing the power of the heat or removing the pan from it. As soon as it smells nice, without allowing it to burn, pour the tomatoes and if you have removed the pan from the heat, place it back on it. Add the salt and sugar and stir, until the sauce thickens.
Add the shrimp, mussels, clams and the fresh spices and remove it from the heat again, by covering the pan with a lid to retain the heat.
Cook the pasta according to the instructions on the package. Strain it well and serve it with the tomato sauce and seafood on top. If desired, you can mix them, but then it is best, that the shrimp are peeled beforehand.
If you are serving the dish to guests, I again recommend peeling the shrimp after cooking them, because along with the tomato sauce, they will be hard to peel afterwards and it will get too messy.
Enjoy your meal!