The dark signal is proportional to exposure time, something that can be easily verified by taking several different exposures. Try this with times of 1, 10, 20, 100, and 1000 seconds, saving each frame with a name that you can recognize later.
Now pick one exposure time like 10 seconds. Take a series of dark frames with the same exposure time, but increase the temperature by 4 degrees for each one. Since you are starting with the detector cold at 2 C, take a series at 2, 6, 10, 14, and 18 C. For each temperature allow some time for the camera temperature to equilibrate to the selection. Save each of these frames too.
At this point you have enough data to demonstrate the use of the CCD camera. Exit from all the programs, and turn off the power strip to the camera and spectrograph.