Hello, as this is your first changeset, I do not reccommend you to start mapping with these complicated things.

1) There already was landuse=railway mapped.
2) It was not necessary to create a relation from landuse=railway as it was mapped as one line.
3) It was not needed to create relation with landuse=railway and public_transport=stop_area
4) building:part=yes is mapped inside of building=yes and it is not necessary to create relation from the building itself

I fixed it.
I reccomend you to start with easier things, like creating point of interests, creating ways, and just then, with some experience create some relations. But if you want to do it, just tell me and I can help you.

If you have some other question feel free to ask Slovak OpenStreetMap community here https://groups.google.com/g/osm_sk