Add a JQUERY script to a CAKEPHP project

We are using a website developed with cakephp. This website is using at one point an javascipt code, and this code is calling a javascript fonction opening a Confirm() pop up. We need to change this pop up into a other one. We already know the script that we are going to use ([login to view URL] see OSX STYLE DIALOG) .? We need you to integrate this script into our web site. It must be really simple, we need that very quickly.