The quilters knot makes a small consistent knot that you can "pop" through the fabric and bury inside the quilt.
Let's see if I can explain it! Hold your needle point up, catch the tail of your thread with the fingers of the hand holding the needle, wrap the end of your thread three times around the needle, catch the wrapped thread between the thumb and forefinger of the hand holding the needle, with your other hand pull the needle almost all the way to the end and release your pressure just before the end of the tail. There should be a knot at the end of the tail!
I hope that makes some sense. :?