How do move imported photos to photos?

Add the photos you want to use in the puzzle in an album and see if you can access the album from the app. Name the album so it's easy to find from the app.

See the articles https://support.apple.com/en-in/guide/photos/pht12e7a8015/mac

https://support.apple.com/en-in/HT204264

https://support.apple.com/en-in/guide/photos/pht5156cc968/4.0/mac/10.14

All Photos are in the Library. The 'Imports' section is just a shortcut to your most recent importing. There is no moving needed.