Remove the cam postion sensor and rotate the engine by hand until the vein is alinged with one of the screw holes from the cam sensor. Mark the base of the assembly to the block. Take the hold down bolt out and gently wiggle the assembly out. Notice when the assembly lifts out of the block the shaft will turn slightly I believe counter clockwise. You will also need to make a vein to body and or engine refrence point. Drop new unit back in gently and make sure it seats properly in the block while and line up the vein with your body/engine refrence point. line up your mark on the base to block and the vein to assembly should be on the money. If not you will have to pull it back out and take another stab at it.
You might want to soak the bottom end of the assembly in some oil before installing. I let mine soak from the oiler hole down in a bottle of Mobile 1 for a few hours so it would be protected durring that dry start up.
A hint: Lets say when you line up the vein to one of the screw holes try to mark the base to block in the same clock position. For instance: standing on left side of car looking down at the vein its pointed at the 3 oclock position, mark the base to the block in the 3 oclock position. If for some reason you have problems and you cant get the vein back perfectly in the position lets say its at 2:30, leave it there and turn the base mark to the 2:30 position. But I'm sure you will get it right the first time
Be sure once you mark everything you dont turn the engine till its all back together and lined up.
Also if you have a digital camera, pic's are also good refrence points...