come on, did you at least study a little before start asking things? spend one hour sarching around and you can find all the answers.
first you need to have your console with a CFW. then its as easy as using ftp to copy the files to your computer, modifying them with the previously mentioned tool and the copying them back to your ps3.
use multimans FTP server to do it.
If you are not using CFW then there is nothing we can do for you.