This is a variation of the popular classic game of Battleship. Both players have to take turns in trying to hit the spaceships of the other player.
You start the game by placing your spaceships around the grid. Select the spaceship you want to move and then press the square you want to move it to. You can also rotate it by pressing the button in the top corner.
When you have positioned the spaceships, the first player chooses a square to shoot. If they get a hit, then they can keep shooting until they miss. When this happens it is the other players turn.