A Task Template is a template for Tasks. When a Task is created, it is copied from the Task Template.
A Task Template consists of Action Templates. Action Templates can be technical like creating a form, executing a Nashorn script, or finishing the Task. Or they can require user interaction. The main interactive action is waiting for a form to be submitted.
A Task Template can contain configuration about which Authorities a Task is automatically assigned to and to which Authorities an assignment is allowed. See the section about Assignments.