Hi Stefan,
the calibration API is a bit complex and difficult to describe, so it’s perhaps no wonder that you don’t find what you expect. But don’t worry, it’s all there!
“Entering calibration mode” means that the eye tracker clears its calibration buffer and prepares to record calibration data.
Then you start to display calibration targets on the screen. As soon as you have one on the screen, and figure that the user is looking at it, you call the addCalibrationPoint function. This instructs the eye tracker to collect data for the given point. There is a small delay (about 500 ms if I remember right) before the actual recording starts. The operation finishes when enough data has been collected, or after a timeout.
Finally you call computeCalibration to compute a new calibration based on the collected data, and stopCalibration to exit calibration mode.