no photos after upgrading older version of Lightroom CC MACbook

HI,

I have been using LR CC 2015ver, I thought it has been upgrading itself but being new to this, it wasn't. It would not perform and update through the menu bar , so I went to my Adobe acct and downloaded LR2019/2020, the most recent version. 

I know have two verisons on my desktop, the old one and the new one. I can open the new one and it has all my work/photos. When I open the current LR, there is nothing. I can upload photos and such, but nothing is linked to the previous catalogs/files ive had .

Is there a link Im missing?, Do I need to move over each file and alll the work I have done individually? 

I updated my Photoshop , It was and old version too. All my work there carried over from the old program to the new. I was expecting LR to do the same.

Using a MACbook Pro

Thanks in advance for any help or insight on this.

Jason S