Cut the dough into four equal pieces, keeping the ones you are not using wrapped in clingfilm.
Flatten one piece slightly and feed it through the widest setting on your Atlas machine (0).
Fold it into thirds, turn it 90 degrees, and feed it through again. Repeat this 2 or 3 times until the dough feels smooth.
Gradually reduce the thickness setting one notch at a time until you reach your preferred thinness, usually setting 6 for tagliatelle or fettuccine.
Dust with a little flour if the dough starts to feel sticky.