Once you've incorporated most of the flour from the inner well walls you might be left with about half a cup of flour. At this point I'd start working with your hands. Knead well. Add more flour if necessary (I had to with this recipe). The entire process takes about 15 minutes.
I tried this pasta dough today. Though I enjoyed my dish I must say that I have come across better pasta dough recipes than this one. I'd try a different one. In my opinion, the dough recipes that call for egg yolks rather than whole eggs taste better. And even though it is worse for your waist line, the recipes that call for 6 or 7 yolks taste the best.
how do you get the flour to form a ball and how long does it take?