Sudoku puzzle instruction

Sudoku Instruction

Features of the game PlaySUDOKU.online

Clear - clears entered values/notes in the cell. The button is inactive if the cell is empty or the value in cell is default.
Notes - allows you to switch on notes mode, in which you can enter all the predicted values for the selected cell. If notes mode is on, the button will be highlighted in yellow (as in a picture).
Back - allows you to cancel the input or clear the cell. If there is no way to make a cancellation - the button will be inactive.
Helper - allows you to block the entry into the cell of values that already exist in the zone (row, column, square), according to the basic rule of sudoku puzzles. It also identifies identical values of cells and notes in them (if any exist) when selecting a cell with a value. If the "helper" is on, the button will be highlighted with pink color (as in a picture).
Hint - allows you to open the selected cell. The button is inactive if: 1) value in the cell is default, 2) value is entered into the cell (true or false) and the "helper" function is disabled, 3) the value is entered into the cell and it is true.

Switched on (yellow toggle switch background) function shows the number of committed mistakes.