help to back to stock H-815T

Please want some help ... i have H-815T V10C-HKG ... i root it ... and now i want to come back to stock to receive updates ...
what shall i do ?
i download (H815T10C_00.kdz) what shall i do ? i hear that many people had soft or hard break when they come back to stock !!
please i want to know what can i do with correct steps ...
thanks