Click a city in the list, then click the map where the dot should land. Coordinates are captured in the same viewBox the live component uses (120 90 880 570). Placements are saved in your browser, so you can come back and tweak a single dot without re-placing the others. Auto-advances to the next unplaced city.
Currently placed dots are marked with ✓. Click a placed city again to re-place it.