docs: improve readme (#7042)

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# Pull Request

## 📖 Description

Starting a local dev server for the website requires install and build in the root directory first. This change reflects that process.

### 🎫 Issues

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## 📑 Test Plan

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## ✅ Checklist

### General

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- [x] I have included a change request file using `$ npm run change`
- [ ] I have added tests for my changes.
- [ ] I have tested my changes.
- [x] I have updated the project documentation to reflect my changes.
- [x] I have read the [CONTRIBUTING](https://github.com/microsoft/fast/blob/master/CONTRIBUTING.md) documentation and followed the [standards](https://github.com/microsoft/fast/blob/master/CODE_OF_CONDUCT.md#our-standards) for this project.

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sites/website/README.md

@@ -4,8 +4,11 @@ This website is built using [Docusaurus](https://docusaurus.io/), a modern stati
 
 ## Installation
 
+Run the following commands in the **root directory**:
+
 ```sh
 npm ci
+npm run build
 ```
 
 ## Local Development

sites/website/src/docs/getting-started/quick-start.md

@@ -75,4 +75,4 @@ Now that the "hello-world" custom web component has been defined, it can be incl
 
 It's as simple as that!
 
-Continue reading through the docs to understand all of the potential ways to use `@microsoft/fast-element` for your website or application.
+Continue reading through the docs to understand all of the potential ways to use `@microsoft/fast-element` for your website or application.