a small-scale tutorialThis may be oversimplified, but sometimes it helps to break down a process into the smallest steps.

Here's a minesweeper grid with all bombs and numbers revealed. The numbers point to the bombs around them.

Here it is again, looking innocent ...
yet deadly.

While wyvernsweeper doesn't have blank squares marked, clicking on any of those blank squares would clear the spaces indicated, because no bombs were there.

Now you look for numbers that have
exactly that many boxes touching them. Because those numbers have exactly that many boxes touching them, those boxes are the only places the bombs that the number indicates could be. Therefore, those boxes are definitely bombs.

Now you look at the numbers next to the boxes you know are definitely bombs. Check to see if the number is the same as the number of boxes you know are bombs.

Any other boxes touching a number that you know has that many bombs already touching it cannot be bombs, so they're safe to click.

All the boxes left are bombs. Yay, you win!