This guide explains how to install iTunes on Windows 10. I'm using iTunes only to make backups, but of course this principle can be extended to all iTunes functions.

• Download and install iTunes

1. Move directory “%APPDATA%\Apple Computer\MobileSync\” or “C:\Users\<user>\AppData\Roaming\Apple Computer\MobileSync\Backup” to the path you want to store your backups, e.g. to G:\iTunes\Backup
2. Shift-right-click within MobileSync and select “Open command window here”
3. Make a sym link (junction in Windows) to this folder:

   mklink /j "C:\Users\<user>\AppData\Roaming\Apple Computer\MobileSync\Backup" G:\iTunes\Backup

4. Make sure iTunes is not running when you make these modifications

1. Move your Music folder to another drive or location in Windows. Right-click on Music, then select Location, and enter the new path. If you want to store iTunes music outside of the Windows Music folder, then follow the next steps.
2. Move directory “C:\Users\<user>\Music\iTunes” to the path you want to store your music, e.g. to G:\iTunes\Music
3. Make a sym link (junction in Windows) to this folder:

   mklink /j "C:\Users\<user>\Music\iTunes" G:\iTunes\Music

• How to change iTunes backup location?