From the project page or reporting page, select a dynamic report.
Find the insight you'd like to filter and mouse over the chart or object:
Click the "Filter" option. A new interface will appear where you can select segments and specific date ranges:
Select the segment to filter by, and update the display name that will appear publicly with the filter:
Hit "Apply Changes" to apply the filter rules to the insight. It will refresh and display the filtered results and filter name:
The public view will be similar, without the admin options: