The Workflow Designer is a powerful workflow modeler purposed for editing and configuring existing workflows as well as creating new workflows. Built on top of the Camunda BPM engine, the underlying concepts, and functionality offered, follow the BPMN 2.0 standard. As such, users should familiarize themselves with the BPMN 2.0 standard. This will greatly facilitate their ability to create and edit workflows.
For those not yet familiar with BPMN 2.0, the link below provides in-depth documentation on the standard.
BPMN Documentation Link
For those not yet familiar with Camunda BPM, the link below provides in-depth documentation on the modeler's principles.
Camunda Documentation Link