Back in 2014, John Kwong opened this topic and pointed at a Chinese TV program about building that boat, in Tianjin (near Beijing).
The Youtube video below seems to be a shortened version of the same thing. However, when I try that original link, I come to a Chinese site where I cannot find my way to that program, so the Youtube clip will have to do.
I suggest you have a look at the discussion from 2014. Here are a few stills that I captured from that TV-program.
...plus this photo - products from the little forge.

Arne
PS: Note the foredeck man with the long stick. My armchair guess is that he kept the foresail sheet in order when tacking or gybing.