ITUNES HELP - can't get songs onto itunes?

I really need someone to help me out here. I bought some songs today off Amazon to put on my ipod, but because my internet connection is the worst it cut off just as my computer began downloading them after purchase. I managed to get that solved, and they've finished downloading. But now they won't go onto itunes. Songs are meant to automatically go to my itunes folder from the amazon one once they've finished downloading, but because my internet cut off it didn't happen.

I'll tell you what I've tried -

Music folder - Amazon downloads - copy and paste it into itunes folder - open itunes library and select "add folder to library" in file.

It isn't working at all, and I need to get them on to my ipod.

Can anyone help me?