A number counts all 8 neighbors, including diagonals.
Numbers say how many mines touch that cell, including the diagonals. Mark those mines with flags. A wrong flag is the only way a step can hit a mine.
The first area is already open and safe. A ring on a number means it already has enough flags. Phone, tablet, and PC use the same rules.
Lower time wins. Short, Field, and Tight are separate boards.
Names and times on the board are public. The flag comes from your IP country.