How to push a NodeJS application to Heroku

Start with these simple instructions:

https://devcenter.heroku.com/articles/getting-started-with-nodejs#introduction

And look for the very short-cut instructions here :)
https://dev.to/smithmanny/deploy-your-react-app-to-heroku-2b6f

Also, look at this article to push nodejs, express app to heroku in 10 steps:
https://medium.com/@grantspilsbury/build-and-deploy-a-node-express-server-to-heroku-in-10-steps-70c936ab15dc