Architecting and designing : Business Process Analysis (BPA) : BPMN : Modeling groups, pools, and lanes on business process diagrams : Drawing Pools and Lanes
  
Drawing Pools and Lanes
You can draw Pools and Lanes on business process diagrams to partition sets of tasks and processes.
1 To draw a Pool, on the toolbar, click the Pool button; then on the diagram, click an empty area.
2 To draw a Lane, on the toolbar, click the Pool button; then on the diagram, click a Pool in which to add the Lane.
A Lane is unavailable to be drawn if at least one Pool has not already been added to the diagram.
See also
Modeling groups, pools, and lanes on business process diagrams