A POCS unit needs some software to run various components. This includes the mount and camera control computers (usually a Raspberry Pi but can be anything), as well as an Arduino Uno for the power distribution.
For the control computers there are instructions for installing the main operating system to run the computer (Installing OS) as well as the PANOPTES Observatory Control System (Installing POCS) that actually does the nightly observing.
There is a simple helper script for installing the code (called a "sketch") onto the Arduino ( Arduino - Power Distribution).