When you click on a random box, it will reveal some empty boxes and some that have numbers under them. Those numbers tell you, how many pataakhe there are in the adjacent boxes. So let’s assume there is a 2 and there are 3 unopened boxes. Then you know that 2 out of those 3 are pataakhas. By logically combining the numbers around unopened boxes you should be able to figure out the ones that have bombs in them and therefore should not be clicked on vs. those that are safe and can be clicked on.
If there is a box where you know for certain that it does contain a pataakha you right-click on that. That will put a flag on it, so you don’t need to remember all the pataakhas while figuring out the rest of the board.