A system includes an input device, a display, and a processor that receives a signal indicative of operation of the input device and outputs a signal to display an image on the display. The processor acquires current terrain data and displays a site image indicative of at least a part of a work site on the display based on the current terrain data. The processor acquires area data including a position and size of a work area designated by the input device on the site image. The processor acquires work data indicative of a work direction in the work area. The processor determines an arrangement of a plurality of work lanes extending in the work direction in the work area based on the area data and the work data. The processor sends an automatic operation command to the work machine according to the arrangement of the work lanes.