Julien,
Thanks for your kind reply and your help. I was moving along an making progress. Then disaster! :)
I was successful in mounting the external hard drive. It appeared in DF. If I then used the unmount command it disappeared.
However it appears I messed up editing the /etc/fstab...
I am new to Linux. I'm trying to set up a Plex server on a Rasberry Pi 4. (Also new to Pi). I have the server created on Pi and have attached an external harddrive with movies to the Pi unit. In the Pi file manager the hard drive shows up on /media/pi/easystore with all the movies in it...