Default [Q] unroot samsung note 8.0" GT5120

I have galaxy note lte gt-n5120 android 4.1.2 baseband version N55120XXBMD9 ,kernel vesion 3.0.31-1189373 6 may 2013,build number JZO54.N5120XXBME1. CSC:AUT
I use odin 1.85 and flash boodloader with CF-Auto-Root/ .it was succeded.
the rom is the stock (no CWM) . the flash counter of samsung go to 1 and use triangle away to reset.
i have inslall extra busybox Free ver 1.2 and Pro version1.3 , Mobile odin version 4.20 , Titanium backup Pro ver 1.2.3, supersu ver 1.9.4 ,Triangle Away ver 3.26,
root explorer ver 3.1.8.
i have a stock firmware from internet.

1) what is the correct proccess for unroot ?
2)Triangle Away app have a setting "System modified workaround" must be check or not during unroot proccess ?

(i have read a lot post if i understand well i must first use " full unroot" from " supersu setting "and after install the stock firmware with Odin3 3.07
and pc .)
thanks for yours anwser.