I dunno. As far as I know the lore doesn’t give any detailed descriptions of it that I can remember.
Since it is a place that honored warriors get pressganged into, I’d imagine it would look a lot like Valhalla but with more flowers and cats and whatnot. Basically Folvang is like Valhalla but good
I think there would be a significant population of non-combatants as well because young women apparently also go there. She might also take seidr-workers and her priest/esses. Maybe Hel gets those, maybe there’s some sort of system.
Personally I picture something that is a lot like the Summerland: bright and sunny and probably full of naked people, and cats.
Folkvangr: It’s Like Valhalla, But Good™
My opinion (and I stress that it’s that) is that Valhalla tends to get the aggressive types, the ones who like to fight hard and party hard – whilst the warriors who go to Folkvangr are the protectors, the ones who want to build something behind a shield.
And places are created as much by the people who go there…