Update README.md

Describing functions and usage

README.md

@@ -4,3 +4,16 @@ This is a simple minesweeper project written in the following technologies:
 - HTML
 - CSS
 - Javascript
+
+The application allows to:
+ - Click on cells of a grid to check if it holds a mine or how many mines are in its environment
+ - In case of win or lose a feedback message
+ - Adjust difficulty level to the users preference
+ - Start a new game
+
+How to use:
+- Open index.html in your favorite browser
+- Click in the grid to start a game
+- In case of lose or win start a new game by clicking "új játék" button
+- Change difficulty by clicking on one of the radiobuttons
+