In terms of getting started as in installing the and configuring the required dependencies locally, we have a get started tutorial https://docs.webiny.com/docs/developer-tutorials/local-setup. In case you don't wanna bother installing all that locally, you can just click the get started button on our website, and register for a managed hosting option - which is currently free during our beta period => https://www.webiny.com/pricing/
The readme on github is just a short summary, but it points you to the docs portal for more info. Since it wasn't clear to you, others might be also bit lost there, so it's something we might need to review :)