The process steps that are part of the maintenance planner's tasks in a preventive maintenance process are:
Create the maintenance plan. This is the step where the maintenance planner defines the technical object, the maintenance strategy, the maintenance cycle, and the scheduling parameters for the preventive maintenance process.
Release the preventive maintenance order. This is the step where the maintenance planner releases the order that is generated from the maintenance plan according to the schedule. Releasing the order means that it is ready for execution and confirmation.
Technically complete the preventive maintenance order. This is the step where the maintenance planner sets the status of the order to technically completed after all the operations and suboperations have been confirmed. Technically completing the order means that no further work is required and that it can be settled and archived. Reference: [SAP Help Portal - Preventive Maintenance Process]

According to the SAP document "Asset Management in SAP S/4HANA Cloud" , task lists are used to assign standardized operations to a maintenance order, and to plan inspections, maintenance, and repairs. Booking time and material consumption on a maintenance order is done using confirmations. Assigning tasks to a notification is done using activities or items.

When you build a communication scenario in SAP S/4 HANA Cloud, you must create a communication system, a communication arrangement, and a communication API. A communication user is created automatically when you create a communication arrangement. A communication interface is not a valid term in this context.
According to the SAP S/4HANA Cloud, public edition Learning Journey1, when you build a communication scenario in SAP S/4 HANA Cloud, you must create a communication system, a communication arrangement, and a communication API. A communication scenario is a predefined integration scenario that enables communication and data exchange between SAP S/4HANA Cloud and other systems. A communication system is an entity that represents an external system that communicates with SAP S/4HANA Cloud. A communication arrangement is an entity that defines the settings and parameters for a specific communication scenario and system. A communication API is an entity that provides the interface and protocol for sending and receiving data between systems.