When I try to get min, max and average lines on bar graphs with a series (e.g.: single bar graph with colors for different categories), nothing seems to happen. The option is present in the properties list but never seems to respond.
The Average, Max, and Min lines and values will only appear when a single series is in use. When multiple series are involved, it becomes unclear whether those calculation are for all series together, a single series, etc.
You aren't doing anything wrong. Unfortunately, these calculations are just not available for multiple series at this time. I would recommend using the Feedback button in the main menu of Domo to relay information about your use case to the Domo product team so they can see how this feature could be used.