docs: make installation guide more beginner-friendly (#6187)

* Add support for beginners

* Add files via upload

* Update intro.md

* Update intro.md

* Update intro.md

* Update intro.md

* Update intro.md

* Edits

* Edits

* Last nits

* Edit

* Update installation.md

Co-authored-by: Joshua Chen <sidachen2003@gmail.com>

packages/create-docusaurus/templates/shared/docs/intro.md

@@ -12,24 +12,36 @@ Get started by **creating a new site**.
 
 Or **try Docusaurus immediately** with **[docusaurus.new](https://docusaurus.new)**.
 
+### What you'll need
+
+- [Node.js](https://nodejs.org/en/download/) version 14 or above:
+  - When installing Node.js, you are recommended to check all checkboxes related to dependencies.
+
 ## Generate a new site
 
-Generate a new Docusaurus site using the **classic template**:
+Generate a new Docusaurus site using the **classic template**.
+
+The classic template will automatically be added to your project after you run the command:
 
 ```shell
 npm init docusaurus@latest my-website classic
 ```
 
+You can type this command into Command Prompt, Powershell, Terminal, or any other integrated terminal of your code editor.
+
+The command also installs all necessary dependencies you need to run Docusaurus.
+
 ## Start your site
 
 Run the development server:
 
 ```shell
 cd my-website
-
-npx docusaurus start
+npm run start
 ```
 
-Your site starts at `http://localhost:3000`.
+The `cd` command changes the directory you're working with. In order to work with your newly created Docusaurus site, you'll need to navigate the terminal there.
 
-Open `docs/intro.md` and edit some lines: the site **reloads automatically** and displays your changes.
+The `npm run start` command builds your website locally and serves it through a development server, ready for you to view at http://localhost:3000/.
+
+Open `docs/intro.md` (this page) and edit some lines: the site **reloads automatically** and displays your changes.