So, actually step for using Root genius, iRoot or Kingo android root is not necessary.Depending what firmware you are right now on it may be possibly (definitely possible with any B6xx and higher rom) to flash the newest SuperSU.zip through a custom recovery. This way you gain root access. To be full rooted you may also delete the set_immutable on B6xx roms.
So, I'd definitely recommend to use the recovery-methode..