A display apparatus of a display system for displaying a video wall image, the display apparatus comprising: a display unit; a connector comprising a high definition multimedia interface (HDMI) configured to receive a video wall image signal and a universal serial bus configured to be connected to an external storage device; a signal processor configured to receive the video wall image signal via the HDMI; and a controller configured, based on identifying that the external storage device is connected through the USB: to obtain a setting information including position information indicating a position of the connected display apparatus in the display system for displaying the video wall image from the external storage device connected through the USB, to set the display apparatus using the setting information, to determine a first sub video wall image to be displayed using the display unit which corresponds to a first position of the video wall image, based on the obtained position information, and to control the signal processor to process the video wall image signal to display the first sub video wall image; and based on identifying that the setting of the setting information of the display apparatus is completed, to change the setting information stored in the external storage device, the changed setting information including position information indicating a position of a second display apparatus in the display system for displaying the video wall image, so that based on the external storage device being connected to the second display apparatus after being disconnected from the display apparatus, the second display apparatus uses the changed setting information to display a second sub video wall image, which corresponds to a second position of the video wall image, based on the changed position information stored in the external storage device; wherein the setting information comprises a number value, and the controller is configured to change the setting information by increasing or decreasing the number value by a predetermined amount. a display unit; a connector comprising a high definition multimedia interface (HDMI) configured to receive a video wall image signal and a universal serial bus configured to be connected to an external storage device; a signal processor configured to receive the video wall image signal via the HDMI; and a controller configured, based on identifying that the external storage device is connected through the USB: to obtain a setting information including position information indicating a position of the connected display apparatus in the display system for displaying the video wall image from the external storage device connected through the USB, to set the display apparatus using the setting information, to determine a first sub video wall image to be displayed using the display unit which corresponds to a first position of the video wall image, based on the obtained position information, and to control the signal processor to process the video wall image signal to display the first sub video wall image; and based on identifying that the setting of the setting information of the display apparatus is completed, to change the setting information stored in the external storage device, the changed setting information including position information indicating a position of a second display apparatus in the display system for displaying the video wall image, so that based on the external storage device being connected to the second display apparatus after being disconnected from the display apparatus, the second display apparatus uses the changed setting information to display a second sub video wall image, which corresponds to a second position of the video wall image, based on the changed position information stored in the external storage device; to obtain a setting information including position information indicating a position of the connected display apparatus in the display system for displaying the video wall image from the external storage device connected through the USB, to set the display apparatus using the setting information, to determine a first sub video wall image to be displayed using the display unit which corresponds to a first position of the video wall image, based on the obtained position information, and to control the signal processor to process the video wall image signal to display the first sub video wall image; and based on identifying that the setting of the setting information of the display apparatus is completed, to change the setting information stored in the external storage device, the changed setting information including position information indicating a position of a second display apparatus in the display system for displaying the video wall image, so that based on the external storage device being connected to the second display apparatus after being disconnected from the display apparatus, the second display apparatus uses the changed setting information to display a second sub video wall image, which corresponds to a second position of the video wall image, based on the changed position information stored in the external storage device; wherein the setting information comprises a number value, and the controller is configured to change the setting information by increasing or decreasing the number value by a predetermined amount.