flashing stock with rsd lite

does anybody know a guide how to flash stock with rsd lite? I can't seem to find a tutorial...the ones iver seen they edit a xml file a delete out lines with "getvar" and I'm wondering thats correct....also do i have to relock the bootloader prior to flashing? not a noob just a first time rsd lite user....can't seem to find a definate tutorial

Download from this link