How do I tell the Photos app to use my iCloud photos as its library?
Basically, I'm trying to tell the Apple Photos app to use all the photos that I have backed up in iCloud as my photo library. Somehow, when I migrated from my last MacBook Pro, my Photos library is blank and lost, shows zero photos. I can only find old iPhoto libraries on my mac, which I can't get to work. Regardless, all the photos I need are backed up to iCloud but I don't know how to have Photos make that my library. I'm not positive I'm asking the right question. Maybe the right thing to do, to fix this problem, is to first try and find out why Photos shows no photos in the first place. Please point me in the right direction. I'm somewhat smart with computers and I'm used to finding answers on the interwebs like most children of the 80's but I just can't seem to find the answers.
MacBook Pro (15-inch, Late 2016), macOS High Sierra (10.13.3)