I feel sorry for that. You need to flash stock ROM through twrp. Then boot into stock ROM. And from here you can proceed to flash custom ROM. Anyway I don't recommend flashing this ROM now as it has no VoLTE and is outdated. Try other ROM that have VoLTE.i just had flashed pixul ui 3.5 for real me 1 and i clicked on advance reboot and their selected boot into recovery and now when ever i try to turn on my device it keep on booting into recovery mode even if in twrp i select boot into system but it again loop into recovery please help me i love this rom for real me 1 but it just broke my heart...please share me the links