# Visual Structure

This help article will help you understand the main concepts used in the scope of the RadScheduler control.

![WinUI Visual Structure of the Scheduler control](https://www.telerik.com/winui/documentation/assets/e30728747a45eb5d2ac3b9438c6837de/radscheduler_visualstructure_01.png)

* **NavigationHeader**: Used for switching the ViewDefinitions of the Scheduler as well as changing the current date. It can be easily hidden by setting the **NavigationHeaderVisibility** property of the Scheduler to "Collapsed".

* **TimeRuler**: Represents the time axis of the Scheduler. The TimeRuler can be vertical or horizontal according to the active [ViewDefinition orientation](https://www.telerik.com/winui/documentation/controls/radscheduler/features/viewdefinitions/configuration). Additionally, you could customize it by following the instructions in [Configuring the TimeRuler ticks](https://www.telerik.com/winui/documentation/controls/radscheduler/features/timeruler/ticks-configuration) topic.

* **Appointment**: Represents a single piece of data that is visualized in the Scheduler. For more details on the appointments, check the [Populating with Data](https://www.telerik.com/winui/documentation/controls/radscheduler/populating-with-data/data-binding-support-overview) topics.

* **GroupHeader**: Represent the date and the resources (when the Scheduler is grouped) headers. The group headers can be vertical or horizontal depending on the active [ViewDefinition](https://www.telerik.com/winui/documentation/controls/radscheduler/features/viewdefinitions/overview) and its orientation.

* **Slot**: Represent the timeslots of the control defined by the TimeRuler. Furthermore, RadScheduler provides the option to create [Special and ReadOnly slots](https://www.telerik.com/winui/documentation/controls/radscheduler/features/speacial-slots).

* **Selected Slot**, **Highlighted Slot**: Represent the selected/hightlighted state of the Slot. The slot selection behavior can be customizing following the instructions in the [SlotSelectionBehavior](https://www.telerik.com/winui/documentation/controls/radscheduler/features/slot-selection-behavior) topic.

* **NavigationDefinition Selection**: Used to navigate between the available [ViewDefinitions](https://www.telerik.com/winui/documentation/controls/radscheduler/features/viewdefinitions/overview) in the Scheduler.

* **NavigationDateTimePicker**: Opens a Calendar for easier changing of the CurrentDate of the Scheduler.

* **NavigationBack, NavigationNext** : Decrease or increase the CurrentDate of the Scheduler according to the ViewDefinition LargeChangeInterval property. For more details check the ViewDefinitions [Configuration](https://www.telerik.com/winui/documentation/controls/radscheduler/features/viewdefinitions/configuration) topic.

## See Also

* [Getting Started](https://www.telerik.com/winui/documentation/controls/radscheduler/getting-started)