After creating your first DMARC record and all subsequent logins to the system you will be directed to the domain overview screen.
From here you can click on each of your domains to see a domain overview of the current DMARC settings and then the details of the reports.
The Aggregate Reports screen allows you to search, classify and identify the sources of your emails along with their alignment status.
You can expand out any of the sources to see the individual message details and their alignment status as well as a link to see the actual XML file that generated the report.