During the placement phase, click on your grid to place ships. Use the rotate button to switch between horizontal and vertical. You can also use the random placement button.
Carrier (5 cells), Battleship (4), Cruiser (3), Submarine (3), and Destroyer (2).
Sink all 5 of your opponent's ships by guessing their locations. Red marks hits, blue marks misses. A ship is sunk when all its cells are hit.