docs(v2): install, create pages, docs, deploy (#1522)

* docs(v2): install, create pages, docs, deploy

* docs(v2): Docs review changes for installation, create pages, docs,
deploy

* docs(v2): more docs!

website/docs/creating-pages.md

@@ -3,9 +3,56 @@ id: creating-pages
 title: Creating Pages
 ---
 
-TODO: Explain the default pages routing behavior and talk about the official pages plugin.
+In this section, we will learn about creating ad-hoc pages in Docusaurus using React. This is most useful for creating one-off standalone pages.
 
-#### References
+### Creating Pages
 
-- https://docusaurus.io/docs/en/custom-pages
-- https://www.gatsbyjs.org/docs/creating-and-modifying-pages/
+<!-- TODO: What will the user see if pages/ is empty? -->
+
+In the `pages` directory, create a file called `hello.js` with the following contents:
+
+```js
+import React from 'react';
+import Layout from '@theme/Layout';
+
+function Hello() {
+  return (
+    <Layout title="Hello">
+      <div
+        style={{
+          display: 'flex',
+          justifyContent: 'center',
+          alignItems: 'center',
+          height: '50vh',
+          fontSize: '20px',
+        }}>
+        <p>
+          Edit <code>pages/hello.js</code> and save to reload.
+        </p>
+      </div>
+    </Layout>
+  );
+}
+
+export default Hello;
+```
+
+Once you save the file, the development server will automatically reload the changes. Now open http://localhost:3000/hello, you will see the new page you just created.
+
+Any file you create under `pages` directory will be automatically converted to a page, converting the directory hierarchy into paths. For example:
+
+- `pages/index.js` → `<baseUrl>/`
+- `pages/test.js` → `<baseUrl>/test`
+- `pages/foo/test.js` → `<baseUrl>/foo/test`
+- `pages/foo/index.js` → `<baseUrl>/foo`
+
+### Using React
+
+React is used as the UI library to create pages. You can leverage on the expressibility of React to build rich web content.
+
+<!--
+TODO:
+- Explain that each page needs to be wrapped with `@theme/Layout`.
+- That v2 is different from v1, users can write interactive components with lifecycles.
+
+-->