No problem.
No extraction is needed just download the file anywhere and double click on the file to run it. Then choose an option and it should just do its thing.
ensure your java is path'd up correctly, and/or update/reinstall it.
It's a .jar - which win-rar can usually read and extract classes and such from it, but it should be runnable like a normal application, it has its own little java applet window for executing its functions with. - if its not running at double click, it likely means either that which I said above, or something else is forcibly taking .jar hooks, but I believe update/reinstall will still address that as well