...BartPE is just a bootable environment allowing you to perform maintenance tasks on your system. For example, for times when your OS buggers up and you can't access it. You can use the GUI BartPE provides to easily retrieve your files if needs be...
...of course there are many more administrative tools as well.
You'll have to read the 'Getting Started' guide to learn how to create a BartPE bootable CD- http://www.nu2.nu/pebuilder/