Use pc or loptop guys..flash mu twrp recovery na compatible sa j2 prime tapos flash mu using odin. Then pag may twrp recovery na phone mu..e flash mu yung super su..yun root na..
Ito hanapin mu sa google.
1.Samsung usb driver
2.Odin
3.twrp recovery na pang j2 prime.
4.super su.
Before mu gawin search ka sa youtube paana mag root..
Take note..dapat tama ang ma flash mu na twrp recovery dahil pag mali ma bootloop phone mu..
Goodluck.