Boil the potato (or wrap in plastic and microwave for 5 minutes at 500 W). Remove the skin, then finely mash with a fork. Add the flour and salt.
Use a spatula to fold the flour and potato together. If it's crumbly, use your hands to form it into a ball. If necessary, add water. Dust your work surface with flour, knead well, then make a tight ball of dough.
Stretch the dough into a 3-cm diameter log, then cut into 1 cm pieces (evenly). Roll them into balls, then, using the back of a fork, press a pattern into them. (This is the fun part of making gnocchi.)
After preparing the sauce, boil water in a pot, add 1 teaspoon oil, then boil the gnocchi for about 30 seconds to 1 minute. Tip: Remove the gnocchi as soon as it floats to the top.
Taste a piece. It's delicious! The photo shows carrot gnocchi. For the sauce, use whatever you like. See: https://cookpad.com/en/recipes/154920-easy-handmade-fresh-pasta.