first download and unzip this Zipfile. it contains a directory "sudokusolv" with the java source files and "Sudokus" with some examples.
Compile: You need "javac" and "java" in your $PATH .. so open a shell and cd to the unpacked zipfile. Then issue "javac sudokusolv/*.java". This generates 4 classfiles in sudokusolv. (You need a java JDK for this).
Run: "java sudokusolv/Main Sudokus/standard-830.txt" (for example, there are some more). Open the textfiles in an editor, you'll get the idea.
Thanks for your patience! - Georg