the adjustable clutch cable will have an adjustment nut on the end where it hooks to the clutch fork. It's pretty self explanitory, turn it one way and you'll tighten the cable, the other way and you'll loosen it.
by the way, with most adjustable cables that i've seen you will have to leave the cover off because the cable is too long
good luck, I hope you dont have a bad back, because its gonna be hurtin afterwards
-Drew