baka flash kelangan mo pra ma root yan.. twrp recovery mode.or try mu mag YøùTùbé baka meron din katulad ng sayo.meron kc pang specific model ung ibang tools pang root like super su.
yes, sa pag root ng marshmallow, need mo ng custom recovery, first step is to unlock bootloader, then flash a custom recovery through fastboot, then flash supersu.zip in custom recovery