To solve you need to determine where the stars are in the grid. There is one star per row, column and colored region. Stars may not be adjacent, even diagonally.

Input tips
To mark a cell as not containing a star, click/tap it.
To mark a cell as a star, right mouse click it or double tap if on touch device.
Alternatively, each time you click/tap a cell, it will toggle through the values, NOT STAR, STAR and unknown (blank).