Few questions about import es6 supported Babylon.js

By following the official tutorial,

import { Engine } from ‘@babylonjs/core/Engines/engine’

import { Scene } from ‘@babylonjs/core/scene’

import { Vector3 } from ‘@babylonjs/core/Maths/math’

import { FreeCamera } from ‘@babylonjs/core/Cameras/freeCamera’

import { HemisphericLight } from ‘@babylonjs/core/Lights/hemisphericLight’

import { Mesh } from ‘@babylonjs/core/Meshes/mesh’

But browser’s dev tool warns me that not files available. However, these files are accessible in Vs Code.
What should I do to import es6 supported Babylon.js properly?

Problem sovled, the path was wrong due to cache, I deleted the entire node_module pakage and re-install, then everything goes well