Running a simple universal example

Hello everyone,

I'm starting with this universal world, and I'm trying to get my web app rendered on the server (includes API requests).
Can anyone tell me some simple and good examples where I can understand the server rendering with API requests?

My API is already online, so I don't need another in React.
I've tried take this project and clean everything (just take the server rendering with two simple components) but can't get it to work.

Thank you all in advance and keep up the excellent work ;)