Noob question: How do I even build this?

[chexo3]

Very new to Java development. I'm used to working in an environment with a build system or something already set up where I can just run <toolname> build or something and have it just work. This has no such thing. I tried my hardest to set up an Ant build for this, but I couldn't figure it out. Can you tell me how to compile it without a build system, so that I might be able to set up a build system in the future? I don't get how to set the classpath and such.