Schema libraries allow you to import one schema to another. You cannot see the imported nodes directly in the code editor but you can see them in the Graph view from where you can inject them into your schema. Imported Graph library nodes are marked with a dashed line.
Every GraphQL Editor project can act as a library. We just cut off the schema keyword. Library nodes are not editable. To edit libraries you should either extend library nodes or edit the library project directly and release a new version.
To attach libraries to an existing project select libraries and click Edit GraphQL libraries.
The library screen will popup
To attach a library, search for it and click the small tick. You can also change the version of the library by clicking a suitable version on the right side of the panel.
To add libraries to a new project, simply click add libraries checkbox during the project creation process, search for the libraries, and select them.