(If you end up with a different page in the browser, make sure that the URL is http://localhost:nnnnn/AddMovie), where nnnnn is the port number that you're using.)
Did you get an error page? If so, read it carefully and make sure that the code looks exactly what was listed earlier.
Enter a movie in the form — for example, use "Citizen Kane", "Drama", and "1941". (Or whatever.) Then click Add Movie.
If all goes well, you're redirected to the Movies page. Make sure that your new movie is listed.