How to configure settings in keystone js on deploying on a Linux server ?

I am developing an app and I want to deploy it on a linux server. I already have copy my local files to the server . I have read this article but not so clear to me https://github.com/keystonejs/keystone/issues/4687.

Question 1: How i am going to set mongo database on production on the server? Question 2 : What are other configuration i do need to set up to complete the deployment and be able to run the node js app ? Question 3 : What would be the mongo configuration i need to do on the server?

Questiom 4: where do i am going to set this MONGO_URI ? and what does this means ?

#Things I have done

• Remote server has appropriate versions of Node.js & npm installed (ideally the same as what you have been testing with in development)

• Check out (or copy) the latest version of your application source to the remote server.

• Run npm install (or npm install --production if this will be a production environment) in the top-level of your application source directory.

#my keystone js settings

keystone.init({
	'name': 'TestApp',
	'brand': 'TestApp',
	'sass': 'public',
	'static': 'public',
	'favicon': 'public/favicon.ico',
	'auto update': true,
	'views': 'templates/views',
	'view engine': '.html',
	'custom engine': cons.nunjucks,
	'mongo': process.env.MONGO_URI || process.env.MONGOLAB_URI || 'mongodb://localhost/testdatabse',
	'auto update': true,
	'emails': 'templates/email',
	'session': true,
	'auth': true,
	'user model': 'User',
});

#.env

NODE_ENV=production @autoboxer