Heres how to do it.
1. Make a low ponytail.
2. Grab a small, finger sized piece of hair from the top of your pony.
Loop it up, over and under your hair tie.
3. Continue to take small pieces and tucking them similarly back into your hair tie.
Do this until you have all/almost all of your hair back into a "bun."
You can make this look as messy or as neat as you want.
When my hair is longer I can make it look really neat for a more formal style.