From your terminal:
npm run dev
This starts your app in development mode, rebuilding assets on file changes.
First, build your app for production:
npm run build
Then run the app in production mode:
npm start
Now you'll need to pick a host to deploy it to.
If you're familiar with deploying node applications, the built-in Remix app server is production-ready.
Make sure to deploy the output of remix build
build/server
build/client