Reports can be added to the dashboard by clicking the 'Add Report' button below the time range selector. Multiple reports of the same kind can be added, and custom data-sets can be obtained by adjusting the individual report's settings.
To remove a report, click the trash icon in the upper-right corner of the report.
Reports added to the dashboard can be configured to change the chart type, as well as the query used to refine the report data. You can change the settings by clicking the gear icon in the upper-right corner of the report. When you modify settings, the changes will be saved when you click the update button.