The rules of the game are very simple. A player can place a point only in such a way that it creates a straight line of five points. Then a new line appears automatically. The lines may intersect and meet their ends, but they cannot overlap even partially. The game ends when no new line can be created.
To navigate, right-click on one of the grid points (small black points) then hold and drag to the end point of the planned line (green points) and release the right mouse button.