I’m pretty new at this, but I’m pretty sure you cut the string about three inches above the belly button, make an overhand knot, and cut off the excess string. Somebody correct me if i’m wrong. I don’t exactly bother with it and just play with the string as the length it comes in… although it probably would be a good idea for me to do so >.>…
EDIT: Actually, I think the knot is the bowline knot… just google or youtube on how to make one