Media Doesn't Appear in Newly Installed Jellyfin

[F4UDash4]

To preface, I am a complete NOOB where Linux, Raspberry Pi and Jellyfin are concerned. Please be patient. I will try to explain in detail my process thus far.
 
I am trying to get my media loaded HDD recognized by Jellyfin.
 
I have an 8tb NTFS HDD containing only a folder labeled “Media”, inside which there are three more folders: “Movies”, “Television” and “Other”. There is 307 Gb of various mp4 media in these folders.
 
I have installed DietPi/Jellyfin on a 4Gb RAM Raspberry Pi 4 via the following (abbreviated) procedure: Download DietPi, write image to SD, install, boot, find IP address of Pi, SSH into Pi via Putty, complete initial setup of DietPi, install Jellyfin. I then successfully accessed Jellyfin in my browser via: http://192.xxx.xxx.x:8097  (NOTE: everything I read online stated that Jellyfin would be on port 8096 but mine was on 8097 for whatever reason)
 
After asking “ChatGPT” for instructions on how to connect an external HDD to the Pi I did the following (using Putty to SSH into the Pi) in order to mount the 8Tb HDD:
 
Create a mount point: sudo mkdir /mnt/external
Mount the drive: sudo mount /dev/sda2 /mnt/external
Verify the mount: df –h
 
All seems to work as it should.
 
However when I access Jellyfin via my browser and add the drive there is no media shown.

What am I doing wrong? Thanks!