Q: What do I do with the iTunes folder I dragged to the desktop during the tutorial, "How to move your music to a new computer"?

try

Deleting files from the iTunes library and your computer

http://support.apple.com/kb/HT3842

iTunes: Finding lost media downloads

http://support.apple.com/kb/TS1408

iTunes Store: Transferring purchases from your iPhone, iPad, or iPod to a computer

http://support.apple.com/kb/HT1848

iTunes for Mac: Moving your iTunes Media folder

http://support.apple.com/kb/HT1449

iTunes for Windows: Moving your iTunes Media folder

http://support.apple.com/kb/HT1364

I assume you are referring to the External Drive method, part five, step 2. If so delete the iTunes folder from the desktop, it is no longer required. The exception would be if you have previously added media into that library before migrating your previous library onto this computer. If so you should move the contents of <Desktop>\iTunes\iTunes Media into <User's Music>\iTunes\iTunes Media\Automatically Add to iTunes to add the media to your active library, then delete the iTunes folder from the desktop.

tt2