You need to remove the rubber grippy part from your shifter. It should pop right off. Assuming you have the post part mounted where you want it, slide the shifter into place, tighten the set screw on the shifter, then slide the HBBC shift "arm" over the twist shifter. The set screw on the arm part should fall between the raised plastic tabs on the twist shifter... Tighten the set screw (not TOO) tight and you're in business.
You can shorten the cable to whatever length you like... Cut the outer sheath first but make sure you use a SHARP cutting tool so you don't crush the metal liner inside. Thread the inner cable into position and adjust the cable at the hub. Then cut the excess inner.
I bet that if you are unsure about cutting your cables, your LBS would do it for you with the proper tools for cheap (if not free...) hope that helps.
If you'd like I can take a couple pics in the am!
JR
