add setup instructions to readme

Author: huang0h

README.md

@@ -4,6 +4,12 @@
 
 ✨ **This workspace has been generated by [Nx, a Smart, fast and extensible build system.](https://nx.dev)** ✨
 
+## Setup
+
+Clone this repo and run `yarn` at the root to install this project's dependencies.
+
+You can optionally install `nx` globally with `npm install -g nx` - if you don't, you'll just need to prefix the commands below with `npx` (e.g. `npx nx serve frontend`).
+
 ## Start the app
 
 To start the development server run `nx serve frontend`. Open your browser and navigate to http://localhost:4200/. Happy coding!