I don't get it. How the F*** does it work?

[Milo-W]

I have a Header ver PL (Polish) and ver EN (English)
I create two pages - one has - or so I thought - the Polish version of the header, the English one has the English version.

I save it, publish, etc.

I go to the website.... BOTH versions have the same version of the header. WHY?
This is idiotic... I thought you are creating a page from replacable blocks (hence "replace") and then I save it stays?

What's the logic behind that?

From initial amazement - first yellow card, Gutenberg!

[Milo-W]

OK so it's still a template I am creating... ouch it's not that clear...