Backing up itunes mp3's and playlist help please?

Hey guys, I am not very knowledgeable with itunes, I am trying to help someone out with his A1398 MBP El Capitan machine and wish to first confirm certain things here please to be sure the guy doesn't lose anything on my account. I need to wipe his HDD clean then reinstall and update to Sierra then put back his backed up files. Only issue is his itunes situation.

I am seeing his mp3's in the Itunes Media -> Music folder so I can copy that out of the mac. I will need to know the situation with his itunes playlist, how can I copy that out together with his mp3's then reinstate on the new OSX Sierra please?

I believe it would be easier if you just moved the entire Music folder, or at least the iTunes folder, then copy it back when it's time.

Oh, so I copy the main folder named itunes and when Sierra is installed, I delete that main Itunes folder in Sierra and replace with the backed up one, would that do it?

iTunes creates the iTunes folder upon first launch. So, if the folder is there before first launch, you can launch iTunes and hold option to select the iTunes library you want to open.

https://support.apple.com/en-us/HT201596

ok thanks, backing up the itunes folder now

Just curios, I have his iphoto library, iphone pics and his photo library but I cannot open the pics on my windows pc, is that normal?