You could create records, which don't have to be related to the record of the workflow. All documentation from "Set value" task are also valid for this task.
There are special tasks for calendar entries, because they have to be created in a special way. Please pay attention what type of Calender Record you want to create. (Event or Task/Todo)
Because of a different internal handling, you must only enter the start date in the field “Start date & time” Also to create a todo it is required to set the Due Date manually by Workflow Designer.
If you want to use the Reminder Feature of Vtiger, you could write any value into the field “Send Reminder”. This value will be interpreted as “minutes before the event”, which will be written to the correct values.
If you click the “Environment” link in the task configuration you could enter a environmental variable, which should hold the id of the created record. This ID could be used later in the workflow.
This is a new feature, which will check the fields you configure for already existing records, before creating the new record. If you set to check E-Mail and LastName field, the task will be search for already existing records with the same E-Mail and LastName Value, like the one you want to create. If they exist, the record won't be created. But if the Task have found an already existing duplicate Record you could configure fields, which will be updated from the configuration you configured for the new record.
To get a check, if the record was created new, you could use the new environmental variable “was_created_new”, in the task configuration. (click on “Environmental” to expand the variable configuration) If the record was created new, these variable will contain a “true” and if not “false”.