To win, you must remove all the tiles from the board.
Tiles are removed by pairs. Only tiles that match (same images) can be removed. There are no more than 4 tiles of the same kind in a game (also called a group). Most of the time, a game has 36 groups of 4 tiles each giving a total of 144 tiles on the board. A tile must be free to move before it can be removed.
A tile can be removed if there are no other tiles blocking it. A tile is blocked when it has a neighbor on its left and its right or another tile is on top of it.
Example:
A tile that can be dragged is hilited when you drag it. While you drag a tile, if you pass over a tile of the same kind that can be removed, that tile will also be hilited. To complete the move, just release the mouse button while you are still over the destination tile to remove. A sound is played when removing a tile. To help you spot free tiles, use the hint command from the options menu.
To remove tiles from the board, you must click and drag a tile on to another one. Click on one tile, hold down the mouse button while dragging the mouse, release the mouse button when you are over the target tile. If the tiles match, they will be removed from the board.
To remove tiles when drag and drop is disabled, you must click on free tiles of the same kind without moving them. The first tile stays highlighted until the other is selected. To deselect, click where there are no tiles on the board.