just hit the string open, with nothing fretted. meh, doesn't matter, i wen around the place asking people what it meant too. i even asked what hammer-ons are, so you're ok
Ego inflating praise here:
Quote by Fishyesque
That is SOOOOOOOOOOO sig worthy! Pure awesomeness to you, sir.

C wut I did thar Fishy?

's UG
0 simply means that you hit the string open without fretting any notes.