As I intend to use prefolds on bb#2 during the first few weeks, I'm keeping these videos for my own future reference.
The first video shows 4 basic ways of folding prefolds using a cover and snappi.
The second video shows folding prefolds without using snappi. But it is not a well recommended method because as the baby moves around more and more, the diaper will shift and you will get a blowout. However, this method will do better than a simple tri-fold.