Q: How to Move iTunes Library BACK to the Hard Drive

Almost every single support topic/YouTube video shows how to move the library to an external drive.  I did that... about a year ago. I recall it being very easy. I just moved, changed the location and that was that.  I want to give my external drive to my friend, though... and want to to move all the content back to the original location on my hard drive... but I'm not sure how/where.  What I THINK I'm supposed to do is copy the music folder back to ITunes Media\Music. 

Ideas?

Thanks