A Sprint is a container of a set of Items for delivery that have been agreed to during Sprint planning by the Team and the PO. Items, which primarily include Stories of the different available types, can be added via drag and drop from Preplanned lists, Kanban lane, Release and generally the left pane.
Once items are added to a Sprint, they can be removed using the option Remove from sprint in their context menus. The items can also be dragged out.
A Sprint can be started from its context menu when it is considered ready. And similarly, the Sprint can be closed when all its Stories are done and will no longer be visible in this view. Consequently, all the Stories will be closed together with the Sprint unless for the special case where the Story was delegated to another Circle.