To be more specific, you'll need to consult a repair manual specific to your 2000 Chevy Cavalier 2.4L. These manuals will have diagrams and detailed instructions on how to locate and replace the water pump. A Haynes or Chilton manual is a good resource, and many are available online (though be cautious of the source).
Remember to properly drain the coolant before attempting any water pump replacement. This job can be fairly involved, requiring specialized tools and some mechanical aptitude. If you're not comfortable performing this repair yourself, it's best to take your vehicle to a qualified mechanic.