First off, just so you know in case you don't realize this, you will need to purchase a shorter belt to work with the smaller pully. I don't know what size is needed for the C-One because I have the UR. If the C-One and UR are the same size, you could look up the size that UR reccomends with their pully (I don't remember off the top of my head, I installed my pully a long time ago)
STEP 1 - Remove the drive belt by placing a wrench on the tensioner and pulling the wrench twards the front of the car to remove the tension. You can secure the tensioner in a full slack position by pulling all the way back on it and inserting a screw into it. The hole that this screw goes in to is located near the bolt that you pull on to remove the slack. I would reccomend doing this because it will make it a lot easier to put the belt back on when you are done installing the pully.
STEP 2 - Loosen the lug nuts on the passenger side wheel
STEP 3 - Jack the front end of the car up and support it on jack stands
STEP 4 - Remove the under body plastic on the car
STEP 5 - Remove the passenger side wheel (without the wheel and underbody plastics on the car, you should be able to see the pully in plain sight at this time)
STEP 6 - Put the car in gear and have a helper step on the brakes to keep the engine from rotating. You need to do this because if you don't, turning the bolt that holds the crank pully on will just result in you turning the engine instead of loosening the bolt.
STEP 7 - the only thing holding the pully on the car is one bolt located in the center of the pully. Remove this bolt
STEP 8 - Remove the original pully. This may be difficult because even with the bolt removed, it's still kind of pressed on there pretty tight. I had a pully puller, so it was easy to remove mine. People have done this installation with out a puller, so it is possable to remove the crank pully with out one. If it is stuck on there to tight for you to remove, you will need to purchase a pully puller like this...
http://www.mytoolstore.com/wilmar/wtech06.html . Its a great tool to have any way, I've used mine a bunch of times. They also work great for easily removing disk brakes that are rusted on to the car.
STEP 9 - If you look at your crank pully you will notice that there is a little groove in it. If you look at the spot where the original pully was, you will notice that there is a little protruding tab that will fit perfectly into the groove. That little tab is called a timing key. Line the timing key up with the timing groove in the pully and slide the pully onto the end of the crank shaft.
STEP 10 - re-secure the new pully onto the car with the bolt. You will need your helper to step on the brakes again in order to do this.
STEP 11 - Install the new drive belt. There is a diagram sticker under the hood that shows you how the belt should go around all the pullies.
STEP 12 - Put the under body plastics back on the car
STEP 13 - Put your wheel back on the car and hand tighten the lugs
STEP 14 - Remove the jack stands and lower the car
STEP 15 - Torque the lug nuts to 76 ft-lbs
STEP 16 - You are done! At this point in time, I highly recomend some form of friendly payment to your helper, such as a cold beer for example. Not only does this make them feel special, but it will will also make them more willing to help you out next time you are working on your car. Every one wins.