Part 3 of the same video is very helpful:
It shows that with a good dough even a novice can pull really thin and even noodles (much better than I did).
I suspect that they add alkaline water to make the dough less sticky. In my attempts when the dough was in a pullable state it was so sticky than it couldn't be operated on. Yesterday I added some alkaline water and it did reduce the stickiness which made the dough more pullable.