Ok we can agree to disagree. I found another thread which has helped me configure this but I still have questions I hope you can answer for me.
I formatted the sd card again, put it in the Pi, created the mount point, successfully mounted it, created a directory, and set permissions to user backup. I did this all as the openhabian user because I didn’t see anywhere that I was supposed to switch to user backup. So when I try to create a file it fails due to permissions, when I try to switch user to backup it asks for a password & I don’t know what that is.
Also, I noticed that in the other thread the OP said he modified the fstab file to make it auto-mount but I don’t see that in your instructions. Is this not needed?