Sounds relatively straightforward. The biggest challenge is that the duration would need to be converted to seconds to be summed, then reformatted for display. If you attach a packaged workbook, we can probably help. Please see Packaged workbooks: when, why, how.
The bar chart sounds very simple, just drag [S Event Description] to the columns shelf and the SUM([D Duration]) to the rows shelf and you'll have your result. This is great if you want to show the total duration spent in a particular event.
Alternatively, you can check out this article from the knowledge base:
That might give you a better visualization.