how to import photos located in pictures folder to photo app

I apologize I am new to MacOS and couldn't find a solution. I have hundreds of photos transferred from my PC and dropped them in the pictures folder. Now I want to import them to my Photo app. But when I open the import menu in the app I can't select the pictures folder. I can only select downloads, iCloud Drive and documents. How can I add them to the Photo app without moving the files first all to downloads or the document folder. It's weird that I cannot choose any folder I want on the hard drive.

Thanks,

MG