Then you should see a page similar to this:

After you see that page, just click the "install" button at the top, or if you have that script saved on your computer somewhere, simply navigate to where you can see it, and drag and drop it on your browser, then you should see that "install" prompt.
After you click install, just head to carnageblender.com and you'll be set! :)
If you have any problem with the forging formulas, you can either A) let me know or B) edit the forging array yourself, if you can figure out how the numbers work, its really easy :)