Place these files in a directory named /appx/ off your web server's webroot.

You need to change three items, all references to www.example.com to read your site URL:

In appx.html
appx.html: ---> var url = "http://www.example.com/appx/appx.jnlp";
appx.html: ---> deployJava.launchButtonPNG = "http://www.example.com/appx/APPXLaunchButton.png";


In appx.jnlp:
appx.jnlp: ---> <jnlp spec="1.5+" codebase="http://www.example.com/appx" href="appx.jnlp" version ="5.0.4b2"> 

Please see our Wiki at http://wiki.appx.com/wiki/bin/view/Main/LaunchingAPPXDesktopClientFromWebPageViaJavaWebstart for further documentation. 
