i want to know how he knocks the arrows to quickly and accurately...
I'm guessing he's using a pinch draw, rather than a Mediterranean or Mongolian draw/hold. The pinch draw wasn't uncommon, and it allowed for very quick "indexing" of the nock against the string.
I also suspect he's using an arrow with a different nock style. Most of us are most familiar with Mediterranean finger holds, and arrows nocked appropriately for that method, but that's far from the only style of nock/hold used traditionally.
With a pinch grip, and a more bulbous, shallow-notched, "cross-nocked" arrow he'd be able to almost ignore the need to line the nock up with the string. He'd hold multiple arrows in his hand, and just open his thumb to slide the string into his hand, pinch the arrow, and draw, allowing the string to fall into place on the nock on its own.
Imagine a nock that doesn't look so much like a slotted screw on the end, but rather closer to a phillips head screw. More like this --> (+) than this --> (l). The notches wouldn't be nearly as deep-cut as we're accustomed to either.
These types of nocks were also more common amongst horse-mounted archers, who might have had difficulty lining up a slotted nock on a bouncing, moving horse. With these types of nocks, you would also likely see a 2- or 4- fletched arrow, rather than a three-fletched arrow with one fletch being a different color...
The type of archery shown sacrifices accuracy for speed, so the deeper nock and using a fletch to index the arrow on the string goes right out the window.
