Add run instructions

README.md

@@ -23,6 +23,17 @@ When the simulator has simulated the requested number of games, it will
 report its results: the number and percentage of wins for each score 
 type, and the mean and median number of rounds it took to win a game.
 
+## How to run it
+
+The simulator requires Python 3.6+, but it doesn't need any third-party
+libraries. To run it, download `potato_game.py`, navigate to the directory
+you downloaded it to, and run `python3 potato_game.py` in the command line.
+This will run the simulator with the default settings: *not* verbose,
+*not* multiwin, *no* potato-spending algorithm, and *10,000* iterations.
+
+To change the simulator's behavior, you can use various option flags
+on the command line. You can use more than one option at once.
+
 ## Game Options
 
     -v, --verbose       Print detailed information about each game.
@@ -34,7 +45,8 @@ type, and the mean and median number of rounds it took to win a game.
     -m, --multiwin      Announce on the console when a game ends in a
                         multi-win. This can lead to a lot of output.
     
-    -i, --instructions  Print these instructions.
+    -i, --instructions  Print these instructions and exit without 
+                        doing anything else.
 
 ### Mutually Exclusive Options: