New Computer: Need to Relink to Library

I'm not sure exactly how to ask this, but I'll try.

New Mac mini
Macmin 9,1
Chip: Apple M1
# of Cores: 8 (4 performance and 4 efficiency)
Mem 16GB

The spouse had to replace my old computer with a brand new one.

She used the Time Machine to reload the new computer. I only use the apps on my computer but keep all the data stored separately on plug-in drives.

Everything is working as it should, passwords, etc.

Calibre Library started up exactly like a fresh, never before used app on the new computer. And doesn't recognize the old library on the plug-in drive. I'm sure I'm overlooking how to reconnect it.

I'm hoping not to have to use something like “add books' to this new library and rebuild all the old changes I made to that library form, if that's possible? I'll certainly start over if I need to.

I'm been looking til I got a headache but only finding links like:
https://www.mobileread.com/forums/sh...d.php?t=172988

and

https://www.mobileread.com/forums/sh...d.php?t=316655

Am I asking the question the wrong way? Is that why I haven't found the right answer?

I'm going to have to go to bed now, so if I get a response before I return, I'm not ignorning anyone.