A mobile device includes a display, a camera to capture an image of a space in which an image device can be installed, a user interface, and a controller. The controller can identify a plane from the image captured by the camera, control the display so as to display a grid on a virtual plane corresponding to the plane, adjust the grid based on an input of a user received via the user interface, and control the display so as to display, on the grid, the virtual image of the image device.