Local Host Installation on Mac OSX not running

When I drag and drop the installation folder to my Terminal and type in
→ php -S localhost:8000 kirby/router.php the startpage is not availabe
under the provided link: http://localhost:8000

also more detailed path doesn´t work:
e.g. user/Users/starterkit-main, user/Users/starterkit-main/index.php

→ I get this notice
This page is currently offline.
We are very sorry for the inconvenience and will fix it as soon as possible.

What could be the causes?
What should I try?


And the message underneath is…

 Advice for developers and administrators:<br>
    Change the PHP version to one supported by your version of Kirby

You need at least PHP 7.4 to run Kirby, please check your PHP version

Enable debugging in the config, so you can see more details about the error.