You'll need a working Java Runtime Environment for your system. I have JDK 17 installed on my Mac, so I will be linking to that version here - Mac - Windows
For Mac, run the disk image you just downloaded.
For Windows, run the executable you just downloaded.
Once you've either cloned the repo or downloaded and unzipped the compressed files, open that directory in your favorite shell ( i use zsh) -- for you non-coders out there, your context window (right-click) will usually contain some sort of "open in terminal" option
- compile the classes
javac Rooms.class Wumpus.class
- run the game
java Wumpus.java