Basically its a towel a little less than 3 feet on each side. I fold it in half the long way, in half the other way, and then in thirds the original direction. You put that inside of the diaper cover, and then put it on the baby just like a disposable diaper.
When the baby pees, you replace only the cloth part. When they poop and it gets on the cover, you get a new cover as well.
For example: https://www.amazon.com/Thirsties-Wrap-Cloth-Diaper-Cover/dp/...
Flour sack towels are thin kitchen towels, I assume named how they are because they are the same material that people used to buy bulk flour in.
The picture is bad, but these are what we bought: https://www.theisens.com/products/flour-sack-kitchen-towel/8...
Basically its a towel a little less than 3 feet on each side. I fold it in half the long way, in half the other way, and then in thirds the original direction. You put that inside of the diaper cover, and then put it on the baby just like a disposable diaper.
When the baby pees, you replace only the cloth part. When they poop and it gets on the cover, you get a new cover as well.