This is a simple logic puzzle where you try to figure out which squares in the grid contain dots, similar to the game Minesweeper.
For an example, press the Answer button now to see the answer for this board. The rows of numbers along the sides of the board give clues about where the dots in each row and column are. For instance, if a row contains the numbers 1, 1, and 3 along the side, then that row has a group of one dots then a group of three dots:
When you think a square contains a dot, left-click in it to mark it. Mark empty squares with the right mouse button. (On a Macintosh, Command-click to mark empty squares.) Some boards may have more than one solution. When you've marked a correct solution for the board, a message will appear in the corner. You should be able to deduce a correct answer for most boards.
You can change the board size with the "10x10" menu, and the density of the board with the "50%". (This density is the probability that a given square contains a dot.) If you are using a black and white monitor, press the "B&W" button.
Try to determine which squares must contain dots first - for instance, there is only one way to fill in a row if the numbers along the side are, say, "10", "8 1", "1 8", or "2 4 2" (on a 10x10 board). If a row contains "8", then there must be 4 dots in the center of the row. Practice on a 5x5 board.