Items Shown per Question
So that the raw scores can be converted to probabilities true to respondents' choices within the context of the questionnaire, you need to indicate how many items were shown per MaxDiff set. For example, it is typical to show 5 items at a time in each MaxDiff question. If you showed 5 items per set, indicate a "5."
Last Item Label
If you used the CBC/HB method to generate scores, the "reference item" (the last item in your study) is not explicitly represented in the .csv file (though indeed it was a part of your experiment). You are asked to supply its label (since that label isn't available in the .csv file). The final item is recognized as the reference item, with a raw score of zero, during import.