These are command-line tools. In order to use them, you will need a command-line environment (terminal). On Mac OS X, use the Terminal. On Windows, you can probably use the built-in shell. But I recommend downloading and installing the Cygwin utilities.
You can download either binaries or the modified source code. Each is a gzipped tar file. Windows and Mac unstuffing and unzipping utilities should know how to unpack these. Or, from the command-line, they can be extracted as follows:
> tar xvzf unixstat-linux.tgz
Once you've unpacked it, read the README for installation instructions.