Nextcloud Reinstall

Due to a power surge my emmc card was corrupted on my Odroid C2.
I have reinstalled Nextcloud and all associated files.
I have attached the HD that I had used before (all data still intact)
I have gone through setting up the drive through device manage routine.
I have rescanned all the files, but it only shows the files from the new nextcloud install.

How do I get my files relinked again.