In most games weeper is done automatically, you can check here https://www.1000mines.com if an empty square is found, but the principle is this: if you find a square without numbers, all eight neighboring squares are safe, so I can use it. Do this until you have an entire outer wall of numbered squares. If you get a numbered square on the first try, start again.

HOLY SHIT THE SPEC OPS MUSIC I'M CHOKING