You need to start sprint on board if you want to use scrum reports.
There are 3 parts in the report: sprint burndown, status of sprint tasks, cards distribution by types and lanes
Unfortunately this sprint was not successfully finished. One of tasks was not completed on time. On the chart you can find information about added completed and removed cards day by day.
You can see details on the end of sprint. For an active sprint you will see the current status.
In the report you can find sprint cards distribution by types and lanes (if applicable).
Note: You will see additional burndown chart if there are child cards of cards in the sprint.