A scenario is an aggregation of different task activities that are visualized by the same business application. An example of such a scenario is, Purchase Order Approval, which is implemented in the SAP system by different task types.
Each scenario needs to be assigned to at least one consumer type, for example, Mobile, Desktop, Tablet. To restrict access to a scenario, you can specify roles for each consumer type and scenario definition. Scenarios aggregate the task definition IDs and system alias from which the task's source originates.