After dinner, set-up the first field (or you might want to do this before dinner to save time). This can be at any given telescope orientation, e.g. zenith. After typing afsetup fieldname, you will be prompted to turn the TV gain down (make sure it is!) and then asked for the siderial time of the observation. Do not set-up a field while the telescope is moving.
Before the TO does the calibrate, take a twilight sky at sunset. About 1 sec should do. This will give you a good sky-offset signal for your first configured field and allow you to define the positions of the fibres on the CCD. A dome/torch flat during the day is also suitable to map the positions of the fibres on the CCD, but not good enough to measure the relative transmissions of the fibres to better than 10%, even if the fibres are in the identical configuration.
Before you start observing, make sure that the ADC is on, although it should come on automatically. If it doesn't try adc_auto enable on the ICL.