folders in photos app

Hi

You can't import into a folder, only into an album.

Folders hold subfolders, or albums. Albums hold photos.

You can drag into a folder from the library - but then an album will be created in the folder to hold what you are dragging in.

See:

Create albums

Group albums in folders in Photos on Mac - Apple Support

First you create a folder in Photos, as you have done.

Depending on your system version, you may need to enable the sidebar with the folders and albums to show.

Then select the photos you want to organize in that folder, where you can see them, for example in All Photos or Imports.

After selecting the photos use the command "File > New Album from Selection" to create an album and name it, then drag it into the folder in the sidebar. Or drag the selected items together to the folder you created to add an album to the folder.