How to replace water pump 2003 jeep liberty

On the 2WD, 4 cylinder, it looks like it involves dealing with the timing belt. Are you up for that? If so, you should get a Haynes Manual.

Nobody here is going to be able to give you detailed instructions on how to do this if you don't have some sort of idea already. By a manual and see if it's something you feel comfortable with attempting to do. If not, you're better off paying someone. I have seen many jobs started by the home mechanic that needed to be finished by a professional and it's really not worth the trouble.