Flash comes from Global Version

[ggkameleon]

Hi ! Nobody can help me please ?
I have a mi 8 global version with Global Dev Rom Pie.
If I want flash Stable Rom Xiaomi.eu I flash Twrp yes but I do to format data before flash The Xiaomi.eu mutli V10.1.2.0 ?
And after for update how flash it ? Dirty flash work just flash cache & Dalvik ?
Thank you ;-)