flow this post: https://didongthongminh.vn/huong-dan-ki-thuat/huong-da%CC%83n-up-rom-tieng-viet-cho-xiaomi-redmi-note-7
NOTE: Do note: fastboot boot twrp.img
after you flash fastboot flash recovery twrp.img , hold up volume and power --> phone will be go to twrp !!!