Welcome to the React Server docs! React Server assumes a separate back end server to serve a JSON api that it can call to get its data, and is a bring-your-own Flux implementation stack. At Redfin, we use Spring MVC and Reflux, respectively, but it shouldn't matter what technology you chose for either. Choosing a tech stack is out of scope for our documentation, but come swing by our slack if you'd like to talk about it.
If you still aren't convinced on React Server, check out our Why React Server doc, which explains why you might want to use React Server, and the Design Doc, which explains why we built React Server and some of the decisions we made along the way.
To get started working with a new React Server project, you'll probably want to check out the Writing pages guide first, which details how to create a new web page in a React Server app. You'll also want to check out the Page API, and you may want to also check out Writing Middleware, which explains how to write code that runs for every route.
To dig deeper into understanding React Server, you may want to learn about how logging works, client transitions, and understanding rendering.