I purchased a price pfister shower kit and it did not have an installation manual. They are closed today and their website does not have manuals on it. I just need to know how to install the valve. Can some one direct me to a site that will give me that info?

Go to pricepfister.com

What is it that you wish to know? If you have a shower valve in place all you should have to do is first shut the water off and remove the old valve. I would keep the old shower raiser and head and just reploace the valve itself.
It is most likely soldered in. If you don't have the equipment and skills to unsolder it and replace the valve you're going to have to call in outside help. Good luck, Tom