I'm not sure this is the correct place to post these questions.
But if you mean item items, then you paste all the files into C:\FeralHeart\media\items
and you paste the items.cfg file into C:\FeralHeart and the replace it with the old one.
If you just get text doc with a code, you open this item.cfg that already exist in the game folder with notepad, then paste the text code in at the bottom and save the file.
If you still need more help, I'd advise you to create a help thread in the help boards.