Help. Change From Unofficial Rom To Offical Rom

Sep 23, 2016

I got my redmi note 2 from *******.
It came with an unofficial rom in it: MIUI 7 by 5.10.16 / Beta
I want to install the offical stable global rom

I have some questions:

1. As you can the Xiaomi provides a flashing tutorial. I want to know if this tutorial will work to change my current unoffical rom to the official rom.
2. I have been told I will lose all my data when i flash it. is there a way to save it?

I dont know anything about flashing phones, any help would be very much appreciated.