Short answer
HubSpot's KB: click a data point on a dashboard report to open the records or pages behind that metric. Use Group data at the top of the dialog to split it by a property, for example one rep's closed revenue grouped by pipeline.
1. In HubSpot
The relevant screen in my demo portal.

2. Worth knowing
The dashboard name menu at the upper left switches to another dashboard without leaving the page.
3. Related
Exporting reports and dashboards on mobile.