How do I link a Western Digital external drive to Mac Studio for Apple TV app and iTunes functionality?

How can I link my Western Digital external hard drive to my Mac Studio (Tahoe) so I can utilize the Apple TV app as I did on my Windows iTunes app. I have 5 Apple TVs throughout my home and this has made them all useless with out the iTunes capability. I have over 6000 purchased and converted to MP4 personal home movie collection as well as my personal Music collection. Also, I cannot control Screen Saver or Play Lists.

[Re-Titled by Moderator]

Original Title: Cannot link external drive