Intro to Java learning lab

I am stuck on the cloning repository stage.
The instructions were:
To test that your project is set up correctly, navigate into the folder you cloned and run these commands:

javac custom_order.java

java custom_order

putting in javac custom_order.java says bash:javac: command not found
I then checked java custom_order and it says Error could not find or load main class custom_order

But trying to clone the repository again it says fatal: destination path ‘java-course’ already exists and is not an empty directory

I don’t know if I am overthinking this or if something isn’t working.
Do I just comment on the issue so that it triggers the next stage and hope it works or?

It says if everything worked as it was supposed to it should have displayed Hellow world which it did not.

This means you don’t have a Java compiler (javac) installed. How to install it depends on to OS you are using.