Note that in this Sudoku puzzle there are three ways to input your numbered answer in each box.
The first method is to type the appropriate number in each box. You do this by left-mouse clicking on the box you want to make an entry and type the number of your choice, 1 through 9, using your keyboard. To clear an entry, type the number zero, 0, on your keyboard.
The second method is the keypad built into the Sudoku program itself. To the left of the Sudoku puzzle is a menu labeled Sudoku Menu. There is an options sub-menu and under that is a button labeled Keypad. When you left-mouse click on this button, the keypad, built into the game, will appear to the right of the puzzle. To use this keypad, first select the box you want to make and entry by left-mouse clicking on it then left-mouse click on the appropriate number in the keypad to make your selection. To clear a selection, press the clear button.
The third method is built into each box of the puzzle. To access this method, left-mouse click and hold for at least 2 seconds to bring up a number selection screen within the box. While holding the left mouse button, move your mouse up and down and note that the numbers increase as you go up and decrease as you go down. To make your entry, release the left-mouse button when your selection is shown in the box. To clear an entry using this method, left-mouse click and hold for at least 2 seconds with the box and then, while holding the left-mouse button, move the cursor up or down, outside the box until no number is shown, then release the mouse button.