Changing the value in the Seed field will generate the corresponding input to the Input field.
Pressing the Download button will download the inputs for seed values seed, seed+1, ..., seed+#cases-1 at once.

By running your program locally against the generated input and pasting the output of your program into the Output field, the visualization results will be displayed.
Pressing the ▶ button starts animation.
By pressing the Save as PNG button, you can download the visualization results.

You can quickly switch between multiple outputs by pressing the Select File button at the top and selecting the directory containing the output files.
By naming the output file 1234.txt or abcd_1234.txt, the seed number (in this case 1234) is automatically set when the file is selected.

The initial walls are displayed as thick black lines, while the walls added later are shown as thick gray lines.
The circles represent the current positions of each robot, and the lines extending from them indicate their destinations.
Hovering over each cell or robot will display detailed information in a tooltip.
When the "show group" checkbox is off, the color of the circles corresponds to the robot number, and when it is on, it corresponds to the group number.
When the "show number" checkbox is on, the robot number or group number is displayed instead of the circles.