You can drag photos to this album, as you would drag songs to a playlist in the Music app.
To create a new album, choose File > New Album. In this article, I’m going to tell you how you can create smart albums, and why you may want to use them. Smart albums, like smart playlists in the Music app, allow you to choose photos by conditions, such as the date they were taken, their location, people they contain, any keywords or titles you’ve assigned to the photos, which camera you used, which lens, and more. An album is like a playlist in iTunes or the Music app: you choose what it contains, and you can view the photos, watch a slide show, use your selection to make a book, and more. You can also organize your photos in albums. But the Photos app does this all automatically, with an algorithm you have no control over when or how these memories are created. The Photos app even creates special 'memories' for you, of photos from specific places, with your favorite people, days when you’ve taken a lot of photos, or even the best photos of your pets.
You can view your photos in many ways: by date, location, and you can even view all the photos of specific people. If you have lots of photos, Apple’s Photos app on the Mac is a great way to organize and edit them. How To Use Smart Albums in Apple Photos to organize your photos
