You click a square, it's either a bomb or not. If it's not, it will show a number telling you how many of the surrounding 8 squares contain a bomb. If a square has 0 bombs in surrounding squares it will just open, so you save unnecessary clicks.
It's the goal to click every square that does not contain a bomb.
If you click a bomb, you lose.
After understanding the rules you can beat the game super quick and easily.
I tried to play it on my google play games app that was pre installed on my phone but I never understood the rules. I did learn to play solitaire on there tho.