Parachute cord or similar good quality cord. Cut a few circumfrential grooves on the shaft (stick). Note; Make sure the grooves are deeper than the cord is in DIA. Use about 4 ft of cord.criss cross the cord in the middle over the hilt of the knife and tie securely. You should have two pieces of cord now attached at the hilt of the knife. with the knife against the shaft, pull both cords to the first groove , cross them and make one wrap with both cords in the groove. Tie and repeat at each groove. When you reach the pommel, wrap and tie. You should have about a foot or so of cord left on each side wrap in a cris cross fashion back towards the hilt Making sure to lap over the wraps in the grooves. and tie off at the hilt. If you feel so compelled, you can wrap tightly with more para cord or duct tape. Depending on the knife, it's easier with some than others, for example, an Air Force pilots survival knife made by K-bar has two holes in the hilt just for this purpose.

It's not hard, practice a couple of times with YOUR knife. Like I mentioned, it's not intended to be a throwing device, but an extension.