What is the best way to understand event based data?

The best way to understand event based data depends on the particular questions you're trying to answer. If you're looking for overall trends in data, then counting the data, perhaps grouped by time frames and another logical grouping, then graphing the resulting time series works best. If instead you're trying to understand how the data is broken down into groups, selecting a time frame as a filter and then visualizing the groups with a heat map or scatter chart may work better.