Home instances are in each racial city, and is labeled as such.
In Rata Sum, it’s the applied development lab, which is accessed through one of the gates at the upper level.
In the Black Citadel, it’s the Hero’s Canton, the northeast quadrant of the map (more or less).
In Divinity’s Reach, it’s the Salma District, which is the northeast section.
In Hoelbrak, it’s the Hunter’s Hearth, which is an upper level in the Great Lodge.
In the Grove, it’s the Dreamer’s Terrace, which is located on the very bottom level.
There’s nothing much else to do there, although your personal story will take you back there relatively often (the level 20-30 quests in particular IINM).
