The Raspberry Pi Camera Modules come as a small board which is attached using a ribbon cable. Here is a video that shows how to do this:
James demonstrates how to unpack and set up the camera board.
The two Astro Pi units on the ISS each have a different Camera Module: one has the standard visible spectrum camera (green) and the other has the Pi NoIR camera (black). These are both five-megapixel cameras, giving high-quality still images and supporting a variety of video recording modes, just like those found in a normal mobile phone. You could program these cameras to record time-lapse videos of the Earth spinning below, or even recognise the faces of the crew when they float near the Astro Pi.