For usage documentation please visit https://doc.babylonjs.com/extensions and choose "post process library".
To install using npm :
npm install --save @babylonjs/core @babylonjs/post-processes
Afterwards it can be imported to your project using:
import { AsciiArtPostProcess } from '@babylonjs/post-processes/asciiArt';
And used as usual:
// Some awesome code
// Creates the post process
let postProcess = new AsciiArtPostProcess("AsciiArt", camera);
// Some more awesome code
For more information you can have a look at our ES6 dedicated documentation.