You don’t need to be familiar with the book, although reading at least the first two chapters will help (they are available as a free sample from Amazon, the one on Orbit’s website is only one chapter which isn’t enough to be helpful).
Your group plays collectively as a single artificial intelligence that controls multiple Ancillary bodies. You, and at least 2 other players (preferably more), have been charged with bringing order to a recently conquered planet… spreading order and civilisation with military precision.
The AI hive mind is simulated in play by using hand gestures that maintain consensus within the group. These are similar to those used by many activist groups (originally Occupy) for meetings and were easy to transfer into an RPG.
After about 40 minutes of world building the game proceeds in a series of short stories, each around 40 minutes long until you want to stop. I takes at least 3 players but works better with more.