Forge App npm run start?

Hello, were building app in jira but question is how to modify forge app to able to run locally with npm? Even if we create totally new demo hello world the app is not runnable locally on browser with npm run start.

Is there way to modify the app code so that npm is able to lounch the code locally?

Edit runnin hello world global page in static/hello world folder starts firefox but arent able to display hello world only blank page.

Uncaught Error: 
      Unable to establish a connection with the Custom UI bridge.
      If you are trying to run your app locally, Forge apps only work in the context of Atlassian products. Refer to https://go.atlassian.com/forge-tunneling-with-custom-ui for how to tunnel when using a local development server.
    
    BridgeAPIError errors.js:4
    node_modules bundle.js:155
    node_modules bundle.js:433
    factory react refresh:6
    Webpack 19
errors.js:4