added Build and run instructions

README.md

@@ -56,6 +56,11 @@ I initilise a variable to hold the user input and then output to ask for movemen
 
 I then use a switch statement to match what key was pressed and to run a function to move the board in the respected way that was inputted.
 
+### How To Run
+
+    Compile using   "g++ main.cpp 2048.cpp -o 2048"
+    Then run using ./2048
+    
 
 # Images