By placing your model here (.glb, .gltf or .fbx), it will be automatically imported in your project. The name of your file will be used to name the variable that will contains your model.
Example:
Take a look at js/World/Suzanne.js:
With a file ./suzanne.glb, you can access your model with this.assets.models.suzanne
You can also organize your models with different directories.
For example, ./models/any/path/to/suzanne.glb find its access with this.assets.models.any.path.to.suzanne