I am trying to back up iTunes to an external hard drive. It only backs up music purchased. I have spent hours importing cds and making playlists which do not copy. How do I get ALL my playlists on to the external hard drive? Please help!!

Select the entire /Home/Music/iTunes/ folder and drag it onto the backup drive then drop it there.

As for your playlist find the .xml file About iTunes library files - Apple Support, (copy it to a thumb drive, email, etc.)

The Home folder is the one with the House icon. It's found by opening a window on your HDD's Desktop icon and looking in the Users folder for the folder with your short-name. That is your Home folder.

You need to consolidate your library so it is all in one folder, then back up that folder (the iTunes folder).

https://support.apple.com/en-us/HT201625

Are you copying the entire iTunes folder in the /Music/ folder? If not then you aren't following the directions. If it's simpler then just copy the entire Music folder you find inside your Home folder. Be sure you have followed all the instructions in here: Back up your iTunes library by copying it to an external drive - Apple Support.

you are trying to migrate your iTunes library to a new computer? if so try this

How to move your iTunes library to a new computer - Apple Support

well first we have to find the physical place of your music, besides purchased ones

Copying music to and keeping the iTunes Media folder organized

You can select these options on the Advanced pane of iTunes preferences:

• "Keep iTunes Media folder organized." Learn more about how iTunes 9 and later organizes your media.
• "Copy files to iTunes Media folder when adding to library." Select this option to store all of your media files in the iTunes Media folder. Since they're all in one location, you can easily transfer or back up your media.
  When you import media into iTunes from a CD, it's automatically added to your iTunes Media folder. If you add media to iTunes another way (choosing "Add to library" from the File menu or by dragging an MP3 file into iTunes), it might not be added to your iTunes Media folder.
  

Locating the file for an item you see in iTunes

If you're not sure where iTunes stores your content, iTunes will show you what it knows about your media in the Get Info window. To access the Get Info window, select a file in iTunes and then choose File > Get Info.

You can also right-click on the content and choose Show in Finder (Mac) or Show in Windows Explorer (Windows).

A remote file, such as one from iTunes in the Cloud, won't show a path, but will show information such as the name of the remote path.

depends on how you added them because they might not be in the iTunes folder, even though you still see them inside iTunes program