It's super simple!
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.
if you're interested, try Antimine on Fdroid, best minesweeper app I've found, and it's open source
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.