The aim of the game is to get a target number of your coloured letters on the board.
The target number of coloured letters you need to win depends on the number of players and the size of the board.
To win you must be the first player to have the target number or more of your letters on the board for two consecutive turns; so, for example, if the target number of letters to win is 30 and you place 30 or more of your coloured letters on the board and there are still 30 or more of your letters on the board when the next player has finished their turn, then you will have won.