There is a tiny green LED on one direction of the unit. The vents are also in the same direction.
Initially, I figured I would point the green LED in the direction of North. Then I decided that I would point them in the direction of the fire evacuation route (not necessary, but a fun way to justify it).
Then I noticed the vents and wondered, should I point those in the direction of some kind of air flow, or pointed against potential smoke flow? I haven't read anything about this so far, but possibly I'm overthinking it and it doesn't matter.