To add a report to a dashboard you will need to first create the report. Please see here to create a report.

Once you have created the report Save the report. Choose a Name for your report, you are also able to change the title of the report. Make sure you select Visible to all users.

Navigate to the Dashboard you wish to add the report to. 

Choose the report you created from the drop down list. You can choose a title for your report that will be displayed in the dashboard. Make sure it is not too long or you will not be able to see the full title. You can also add a description which will be displayed on the top right hand side of the report. Click Save.

The report will now appear in the dashboard.

If you wish to Edit or Delete the report double click on the icon.