Choose a cell on the 9x9 grid to start your Sudoku puzzle. Place numbers from 1 to 9 in the empty cells, ensuring each number appears only once in each row, column, and 3x3 sub-grid. Utilize the notes feature to note possible numbers for a cell if unsure. Remove any mistakes by selecting the cell and pressing the erase option. Finish the puzzle by filling all cells correctly without repeating numbers in any row, column, or sub-grid. Switch between easy, medium, and expert difficulty levels to test your logic and problem-solving skills. Verify your progress with the help feature if stuck, but aim to solve as much as possible on your own for a satisfying experience.