To interact with the boxes of the grid, simply click the left mouse button. Different modes of interactions are available :
The mode ''Writing'' (default mode selected in the upper right) lets you fill normally sudoku grid. To fill a box, click it once and then click once on the number to insert.
The mode ''Marking'' allows you to mark or erase small numbers inserted in the boxes, each box containing 9 small numbers. To mark or remove a small number, click once on the box and click once on the number to mark or erase.
The mode ''Reversed marking'' works like the ''marking'' mode, but in this case, all the small numbers are marked except the one selected first.
The mode ''Deleting'' lets you erase the contents of a case (number and markings) To clear a box, simply click it once (when the contents of boxes removed, do not forget to change the mode)
Just below the modes you have different options :
The option ''Previous step'' allows you to undo the last operation you performed.
The option ''Next step'' allows you to return to the last operation that you canceled.
The option ''Detect errors'' allows you to ask the program to report double numbers in lines and squares.
The option ''Reset all'' allows you to restart at the beginning, with all the empty boxes.
Just below the options you have different information :
The information ''Chrono'' gives you the total time elapsed since the display of the grid until its resolution (the chrono stops when the grid is resolved)
The information ''Step #'' gives you the total number of operations performed since the display of the grid.