The main BP includes the user activity, and invokes the sub-process created in the previous step.
Create a BP, and add the modeling elements including a user activity.
Link the modeling elements together.
In the Project Explorer, expand the sub-process, and then drag the operation of the sub-process onto the user activity in the BP. This node is named Operation by default, but you can customize the name in the WSD object.
Create the business rules for the links to define the mapping of data.
Define task assignment for the user activity, as described in Defining Task Assignment.
When you are done configuring the modeling elements, click Save on the Enterprise Designer toolbar.