For usage documentation please visit https://doc.babylonjs.com/extensions and choose "loaders".
To install using npm :
npm install --save-dev @babylonjs/core @babylonjs/loaders
Afterwards it can be imported to your project using:
import "@babylonjs/loaders/glTF";
This will extend Babylon's loader plugins to allow the load of gltf and glb files.
For more information you can have a look at our ES6 dedicated documentation.