After you imported your model you can search for elements by their id or by the type of element.

You can also access the child elements of an element or references to other elements. For example, a plan itemreferences a definition element (like human task, process task, etc.) while the referenced definition element containsdefault control.

You can now use the CMMN model API to get the definition of the plan item with the ID PI_HumanTask_1.