There is a link directly to Apple's iTunes 8 tutorial also. Did you see that?
The basics in iTunes have never changed. Main changes have been they've added little extras. Even if you were seeing iTunes v.1 tutorial, it would apply to now. I've used every version since version 2.

Drag & drop works for me now from any where on my computer I have audio files. Not sure why it is not working for you. Works exactly as those sample images show.