Heya :) It depends a bit on what the facility is, but generally the approach is to have an area which forms the outline of the facility, and that has the tagging on it for the facility itself. So in the case of a complex train station, it’s recommended there’s an area which encompasses the whole passenger-accessible part of the station, and that contains tags like the station name and operator. Buildings within that area are tagged only with building-specific properties, such as the number of storeys they have and their material.

The wiki has some good examples: https://wiki.openstreetmap.org/wiki/Railway_stations and it’ll probably also have examples for other large common facilities.

I hope that helps? Happy to answer questions if it doesn’t!