Create projects using third-party extensions
You can use third-party extensions to create projects such as print products, slideshows, and customized websites. Go to the Mac App Store and look for apps that include Photos project extensions, then download and install them to use them with Photos. For more information about installing extensions, see Add editing tools and extensions to Photos.
Create a project using a third-party extension
After installing a project extension, choose File > Create, then choose the extension you want to use.
You can also click next to My Projects in the sidebar.
Follow the on screen instructions to create your project.