Peel and boil the potatoes.
Then mash them with Parmesan and add salt.
Roll out your dough on a pastry board (not too thin) and then add your potato and cheese filling. Close it into a ball.
Roll it out with a rolling pin. If you break it and the excess filling comes out, don’t worry, it can happen! Don’t give up!
Just remove the excess filling and try to fix it closing the small holes.