Photos Library on iMac - where is it

Old Toad,

Really appreciate your help. I may be too much of a novice and I don't want to waste your time. Feel free to tell me you don't have the time to deal with me.

I am running Monterrey version 12.4. and I don't understand how I would go to a Photos library from an email or message.

The "Migrated Photo Library" shows a size of 4.14GB, but I don't see any files at all.

The "Photos Library" shows a size of 18.57GB but see no files.

I don't see any "Originals" or "Masters" folders.

I don't know how to get to the window you are showing above. I guessed it was in System Preferences, but I don't find any such window there.

Thanks again for your help

Sorry for delay.

My computer: iMac 27inch, 2020

In looking further I have found that I have a third photosLibrary file: Photos Library.photoslibrary. Shows size to be 858bytes.

So it looks like I have 3 separate library files; the one mentioned above and iPhoto Library.photoslibrary size 18.45GB and

iPhoto Library.migratedphotolibrary size 4.14GB. If I double click on the iPhoto Library. migratedphotolibrary file I am unable to open. If I double click on the iPhoto Library.photoslibrary file the Photos app opens and I see all of my photos. If I double click on the Photos Library.photoslibrary file nothing happens. This seems strange since as I remember the old version of operating system used an app named iPhoto and the new version uses app named Photos.

The Photos general preference pane shows: Library location; user name>photo library>photoslibrary and the second line

shows: Show in Finder and Use as System Photo Library and the second term is NOT greyed out.

Seems like I have a confusing mess. No idea how it got this way.

I have 2 files: iPhoto Library.photoslibrary and iPhoto Library.migratedphotolibrary but when I click on either one there are no files showing.