How to add library from mounted ssd with games on it? Linux

So, long story short, I got new pc and I have ssd (that has linux instance on it too) drive from my laptop that I have successfully mounted on my system.

Problem is, I really don't know how to add my existing game library from mounted ssd to steam, and so that future downloads would be loaded there.

When I click "add" it throws me into file manager and I cannot figure out what to do, instead of the drive selection.

I'm pretty sure I've mounted my drive correctly. It persists throughout reboots and everything.

Should I just reformat my drive at this point? Or is there a way to get access to my games from that ssd?