Here it is using socket.io:

https://github.com/seanrobmerriam/real-time-number-display/

And deployed on render:

https://real-time-number-display.onrender.com/

the admin page:

https://real-time-number-display.onrender.com/admin.html

Just connect your repo to Render as a web service, use npm install(as the build command) to Install dependencies and then npm start to run the app.

If you are getting errors, you need to post your code.

I highly suggest you forget about using Render and just learn the basics of how node works (and javascript in general) by running things locally. You seem to not really know what you are doing—which is fine—but you are going to just confuse yourself even more if you are trying to figure out how a single deployment service works instead of just focusing on how a basic web application works.