I have implemented redirections, which are basically just HTTP status codes that point the site to a new page. The command is:
The way it works is that if the logic in your code (say, successfully signing in) should then move you to another page, it does so and immediately exits, without printing anything else, even if you have put (display-page) later on in the page. So, in our example, if the username and password are valid, it just puts you back to the main page. If they are not valid, it will display a message normally with (display-page).