If a stage is collapsed, only its name and a plus sign are displayed:

A stage is defined in XML as follows:

Note: The listed plan item definitions inside the are referenced by plan items in the case plan model itself (i.e., stage), as well as by plan items in nested stages. Plan item definitions must not be contained by any other stage than the case plan model.

A stage in state ENABLED can be started manually using the CaseService as follows:

Camunda Extensions