I will discuss how to use these cameras and give some useful details about placing an object on the slit. The slit viewing camera lets the observer, with the help of the night assistant, place the target object on the slit and possibly improve the guiding. In the near future there should be a facility for easily transferring slit camera images to the observer. Until then, the night assistant controls the slit viewing camera. It is, however, up to the observer to place the object on the slit.
Long exposures require guiding.
The guide camera can pick up stars of a faint enough magnitude that one should be able to, in theory, guide anywhere. It is still more accurate to guide on the object on the slit or a object nearby your target using the slit viewer. To use the guide camera, notify the night assistant that you would like to guide. They will look for a guide star. If you do not care about the rotator position for the observation, let the night assistant know.