Mouser has put up a screen shot, so here's some blurb & the program attached - I hope!
To solve the puzzle, fill in the grid so that every row, every column, and every 3x3 box contains the all the numbers 1 to 9.
The game digits are centred in the middle of the cells. The starting digits are blue, subsequent digits are black.
If you click "HintsOn", all allowable digits are shown in small grey at the bottom of empty boxes.
The top of the cell is for personal notes.