You start with parting your hair like a half ponytail. Split that section in two ponytails. A top and bottom.
Part the top hair in half and bring the bottom ponytail up and through the top one and secure it out of the way. You then tie a new ponytail with the hair you brought down and repeat the steps.
Repeat the same steps until you run out of hair .
Gently pull at each hair tie like you would be tightening a ponytail to make it chunky.
Continue with your ends. Split the last hair tied in two and bring it under the hair that was at the bottom and tie it.
You can also pull more for a bigger effect. :)