Better clarify prerequisites in README's (#338)

* Yarn

* Improve Prerequisites section for ReadMe's

* Adding development environmental link

README.md

@@ -17,8 +17,9 @@ If you have an existing React Native project, it's easy to begin using FluentUI
 
 ### Prerequisites
 
-- [Standard React Native dependencies](https://reactnative.dev/docs/environment-setup)
+- [Standard React Native dependencies](https://microsoft.github.io/react-native-windows/docs/rnw-dependencies#manual-setup)
 - [Node.js](https://nodejs.org/en/download/)
+- [Setting up your React Native Development Environment](https://reactnative.dev/docs/environment-setup)
 
 ### Create New React Native project (if needed)
 

apps/win32/README.md

@@ -1,5 +1,12 @@
 `FluentUI Tester` is the test app that we use to test our FluentUI components during development.
 
+## Prerequisites
+
+- [Node.js](https://nodejs.org/en/download/)
+- [React Native Windows Development Dependencies](https://microsoft.github.io/react-native-windows/docs/rnw-dependencies#manual-setup)
+  - **NOTE:** Please make sure you grab all of the items listed there and the appropriate versions.
+- Enable [Developer Mode](https://docs.microsoft.com/en-us/windows/uwp/get-started/enable-your-device-for-development) in Windows settings
+
 ## Launch `FluentUI Tester` app
 
 1. Make sure you have followed the Getting Started instructions [here](../../README.md) to install packages and build the entire repository.