Boil 5 cups of water with 1/3 cup salt.
When all salt dissolved, remove from heat, let cool down to 122 F (about 5 minutes).
Pour the warm brine into cabbage container, use a spatula or some thing to stir around so that all pieces are loosen and in contact with the brine.
Apply some pressure to make sure the cabbage stayed down. (I used a heavy water bowl over a crossed skewers).
After soaking with brine for 10 minutes, stir to flip the cabbage upside down, again, keep them down and soak for another 5 minutes or so.
The napa cabbage should now be more bendable without breaking but still preserving their crispiness.
Fill the container with water, and rinse off all the brine once, or twice if you feel them too salty.
Drain off all excess water, you probably have to squeeze them a little, and place them on a basket or cooling rack to drip off excess water.
Shred all other accompany veggies like turnip/daikon radish, carrot. Cut off the white stem, and chop the green scallion.