As described, the C15 has two different user interfaces. The User Interface consists of the Unit and Unit with their haptic ("hands on") controls.
The User Interface is available on external devices via a Wi-Fi connection, and offers a detailed representation of all parameters and presets. Multiple devices can be connected in parallel, each focused on different aspects.
Note that all available interfaces operate in a synchronized manner, sharing the same state and focus.
The following chapters explain how to focus on items and their aspects to edit them.