I've been looking for a while for a good summary of how to vote that I could link to people, but not even on europa.eu do they have that, which really speaks for itself. If anyone knows of a good source, I'd love to know about it.
The selection is based on the display language. If you're a native English speaker voting in the upcoming election, you're aussumed to be voting either in your home country (Ireland or Malta are the only ones where English is official) or "abroad", which is the third option. German speakers would be expected to visit https://www.europawahl.eu/ instead.