need some help flashing a rom
i'm following steps to install monxdifieds rom and in the instructions it says
"Turn off device. (Hold power button + vol up until vibrates 3 times) [or use recovery turn off device option, if any]
Flash latest Sony's firmware (FTF) matching current latest monxDIFIED base rom using flashtools. Uncheck all WIPE options and exclude all EXCEPT KERNEL & BASEBAND to get latest matched kernel & baseband."
I don't fully understand what it means to flash sony's firmware matching current latest monxdified bas rom, could someone explain to me what this means? how would i go about flashing the sony firmware?