"When mutants kill and destroy all that matters in your life---What can you do? As the last hope of a dead town, will you seek justice for the dead and help for the survivors? Or will you lose your way in this big nasty world that's waiting for you? Can anyone, for that matter, good or evil, survive for long in a world where most problems are solved at the end of a knife or with a burst of gunfire?"
Download the file on your hard drive and double click on it. When the Installer window appears, choose "Install" and follow the instructions on screen.