Use Arrow Keys or WASD to navigate the puzzle board. Use the Number Bar to insert your guesses. Hold Shift to add pencil marks. You can also use the Number Pad to add pencil marks. Hold Shift to add your guesses. Clear a cell with Escape, Delete, or Backspace.

Left Click a cell to open the Number Picker, select a number to enter a guess. Right Click a cell to add pencil marks. Middle Click will clear a cell.