If a report is required in CSV format, the SIEM only allows you to use what it calls “PreDefined Queries”. You can not edit or create these from the report interface, though you can add additional filtering after. To create a new predefined query, or edit an existing one, you'll need to do it from the edit dashboard panel. You can either create new dashboard or edit an existing one.
Create a new Table (bar charts, lists, etc. don't seem to work). The Query Wizard will pop up with a list of queries we can edit, including any ones we've created. Here you can edit them by clicking Edit, or Copy an existing one to create a new one.
If creating new, copy the “Events” Query and give it an appropriate name (looks like about a 40 char limit on names), click OK
Select the Report you are creating or want to Edit and Click Edit. I would recommend against editing any of the default ones, instead copy them to create new versions for your use.
This brings up the Query Wizard where you can define the fields in the Query, and Filters, and a Sort order
Once you have the fields, filters and sort order in place, Click Finish on the Query Wizard. This will save the Query and it is now accessible for CSV reporting.
At this point, you are back to the window to create the chart in the dashboard. You can close the window and delete the dashboard as it is not required for the query
Now, when you create a report and use the CSV option, the query you created here will be listed in the pre-defined query drop down. Please be aware that the list is alphabetical, but treats upper and lower case characters differently so AB will come before Aa.