Closed samsung j5 help plsss

mga master jan pahelp naman po about my samsung j5 sm-j500g
rooted po phone ko pero wala naman ako dinelete o ginalaw sa system .after 1week tg try ko ion yung KNOX PROTECTION nya then yun nagrestart tapos stock na sa logo nya . triny ko dn installan rom using recover pero pwede kc once na eclick ko yung install from external di daw pwede kc naka disable . help naman po plsss

na try mo na po ba using internal memory baka kase nka write protrct ung external.

Boss panu mo naroot J5 mo ? thanks