Well, firstly, restoring does just what it says- restores. if you have to restore, everything will go back to normal. Hopefully it wont come to that though.
Secondly, in number N45AP.plist, you should see sets of code set apart by different indentation spaces. Copy ONE of these "sets." it shouldnt be too hard to pick out one set form another. if you;re getting a block of text instead of formatted code, you NEED TO EDIT IT in a PLIST E

ITOR. Idk if notepad or wordpad will work with this- google around for a windows plist editor- or if on mac downlaod BBedit.
Thirdly- Its pretty much impossible to 'brick' an ipod touch without some sort fo physical damage- worst case, you screw up and have to restore.
It doesn't matter how or where you back the files up- you jsut need them in case something fails and your ipod wont respring, etc, and if that happens you can replace the changed files with the stock ones to fix it.
also, make sure you replace the files on the ipod, or nothing will happen. not sure what you meant by that, but yes. save teh changes to the ipod lol.
I cant recommend doing this if you dont fully understand whats going on- the terminology is pretty simple for JB users, and teh directions rather straightforward. i would at least become a little more familiar with the system before doing things like this unless you're ready to restore a few times in the learning process.
Also, i have found recently that this kind fo disables ipod use in some ihome devices- I have to manually push play on my ipod to start playing, the ihome play button on the ihome and on the remote don't work anymore, although this could be due to another of my extensive hacks installed... all else works (Speakers, next/prev buttons etc.) however be warned if you have an ihome. other than that no issues have surfaced.