Place stars into some empty cells so that cells with the stars do not touch each other even at a point. Each arrow should point to exactly one star. Numbers outside the grid show the number of stars in the corresponding row or column.
Grid control: Click the mouse button at the selected cell to set/remove a star. Second click will put auxiliary cross sign, which doesn't affect correctness of the solution, but helps visually. You can also drag the content of one cell to another with the mouse. More details about grid control are at the help page.