dude u need to get rcon and type this in the console (shift + ~) to open the console.
so type this rconpassword eg.hi
if that was ur password it will work

You have to get a mod.No just kidding you need to enter the main menu in the
begining.Before you click on load new ect. Type helpusobi 1 then type set
g_sabermorerealistic 2 or 3 depending on the damage you want . NOTE certain level take a
few kills to start dismemberment.

To have fun with dismemberment go to a saved game. Then enter in the console notarget and
then npc spawn (any enemy). Now ignite your saber stand by the enemy if you followed my
tutorial on how to turn dismemberment on (above)then you should turn your saber through
the enemy if thier killed just by the touch of your saber dismemberment is working. Have
fun!