Unable to add bpmn-js web-based diagram to my application

Users
1

I Done walkthrough of Bpmn-js but I couldn’t able to add bpmn-js to my application I dont understand which file i have to use in my application and

2

…and what?

Let’s start with a very simple example: https://codesandbox.io/s/hello-bpmn-js-svgrr?file=/src/index.js