Drag a Tuple Based Window operator from the Palette to the Design view.
Connect the output of an operator that has stream output to the input of the Tuple Based Window operator.
Double-click the Tuple Based Window operator.
The property editor opens. The attributes of the input schema are displayed in read-only mode.
In the Size field, specify the number of events.
(Optional) Click the Documentation tab and supply notes on this component.
Click OK.