The Task Scheduler icon, located on the WorkCenter Menu  is a quick link to common tasks, such as depicted in the below image.

With a contact chosen in the Contacts List, choose a task and it will then be added to the WorkCenter Task Manager, it also creates a Journal entry if you have set that up in WorkCenter to do so. See Journal entry

NOTE: When you select a task, the task will appear in the Task Manager initially and not in your calendar. You can drag and drop the task from the task manager to the calendar and also back into the Task Manager when you have mark Task Complete. See Task Scheduler and/or  Task Manager.