Kind of tutorial, install postmarketos on Xiaomi Redmi S2

I tried to explain there in mastodon how to install postmarketos on a Xiaomi Redmi S2, step by step.

I intend to help beginners and democratise at maximum, because I mean linux phones are far better than custom aosp derivatives with uncertain future.

My kind of tutorial is unperfect and needs improvement, to make

in the future.