This feature is available in Enterprise and Ultimate editions.
To view the workitems related to a particular sprint, select a sprint from the drop-down list at the top of the TeamRoom.
Beginning in the Spring 2017 release, the Storyboard will show backlog items by roll-up categories any time multiple workspaces with different status values are detected. This will occur if one or more Teams that own work in the backlog has defined a Team specific process of if the currently selected project has child projects with project specific workspaces that use different status values.
For teams who have enabled the Team Process Management feature, see What impact does defining a team process have on my instance? to learn what impacts it has on TeamRooms.