Adding a report to the dashboard is the same concept as adding a widget as per our help documentation (https://techdocs.broadcom.com/us/en/ca-enterprise-software/it-operations-management/cloudhealth/saas/index/getting-started-with-tanzu-cloudhealth-getting-started-index/getting-started-with-tanzu-cloudhealth-getting-started-with-cloudhealth-dashboards.html)
To do so, edit the dashboard and drag the report widget onto the layout:
You can then select a report: