It's easier than it sounds if you follow the YouTube video from a few pages back.If I knew what any of that meant, i'd be all over it.
Basically what you're doing is starting the phone in a different mode, connecting it to a PC, downloading a few files, typing some commands on the PC to make said files 'root' the phone, then once you have a 'rooted' phone, you can load a file onto it, install (flash) it on the phone and you're done.
In very simplified terms anyway lol. The video guides you through all that though.