Wrong forum and I think you should do some reading before actually trying out stuff.
My recommendation is, before applying themes or other modifications, nandroid backup is always a good idea. For the theme/framework modifications on this forum, there are a few options. One might be flashing the zip file through clockwork recovery (if the themer has posted the file). If framework-res.apk is just posted, you can try using adb or root explorer and replace the new framework with the old framework.
Again, some reading would help
TELUS Galaxy Note 2 SGH-i317M
Past phones: Bell Galaxy S II, AT&T Captivate, HTC Magic 32B