CamStudio isn't intended to be a "video recording software" like a product that you would use to record and edit videos taken with your video camera. It records what's on your computer monitor and makes it into an AVI video that it will convert to a SWF Flash movie.
The operator can include voice-overs and add text to the screen. It's very useful for demonstrating how to use software or show off your skill at landing a 737-400 on MS Flight Simulator but I wouldn't try doing a remake of "Gone With The Wind" using CamStudio. :-)