This is just a couple of very basic example classes to illustrate the first steps of understanding how OO programming works.
I'd suggest downloading the zip and creating it as a new folder on your machine, then running docker compose up -d
to get the environment up and running.
If you then visit http://localhost:8885/ you should see the output of the index.php
file, and if you look in src you'll find the three files driving the output.