Now all you need to do is upload your index.html and config.xml files. Click upload and drag them in. Then in your tab that starts with Adobe (if you can't find it, open https://build.phonegap.com/apps). From here, upload this gist and click select master. Your all set!
If your still confused, please look at your scratch tab or open https://scratch.mit.edu/discuss/topic/236734/?page=1#post-2415174.