The Communication Centre contains various forms of communication with internal and external persons with whom you are in contact and collaborate. Including, notifications (you will be informed about changes regarding information you are interested in) and message box (formal communication, question and answer and status exchange around a process)
The Process Navigator element supports a phased approach in any form of work where it must be performed sequentially. Each phase within the process can have its own interpretation and defined lead time, e.g. associated actions or documents. Think of project-based work.
Structured collab gives structure to information when working with people inside and / or outside the organization. This element can be combined with Process Navigator, in which you work together in a structured way.