well, the definition of putting a new rom on your phone is flashing it. it's really not difficult to flash it though. i did it for the first time today to my new TP and it was cake. (of course, i flashed my vogue and treo back in the day, but it was a slightly different process)
i see you have a CDMA TP, so follow the directions
here and then
here
i prefer the sd card method