The panel is the control bar across the bottom of the screen, used to find and launch applications and navigate among windows and desktops. It contains the K menu (identified by the KDE K logo), which organizes the installed KDE applications into submenus; the Desktop Access button, which minimizes all open windows to display a clean desktop; and the desktop pager and the taskbar. Additional buttons that open applications, directories, and URLs can be added to the panel.
Like most window managers, kwin (KDE’s window manager) can divide your workspace into multiple desktops. Different application windows can be open on each desktop, reducing the amount of clutter on your screen. You can switch among desktops by using the desktop buttons on the panel. The panel displays a grid of buttons called the pager . The pager has one button for each virtual desktop, and shows images of the open windows or their names (1, 2, 3, etc., by default). Clicking on a button switches your screen to the corresponding desktop.
Clicking the wider vertical bar to the left of the pager opens a Desktop Pager window. If your version of KDE does not have that bar, right-click on the pager itself and select Launch Pager. The Desktop Pager has larger buttons for each desktop and an actual icon for each application running on that desktop, making it easier to tell what applications are running.
You can configure the number of virtual desktops and their names in the Control Center by ...