Docs : Update getting started post

src/posts/blog/getting-started.md

@@ -7,4 +7,85 @@ thumbnail: "./images/getting-started/thumbnail.jpg"
 alt: "apple and shaking hands"
 ---
 
-## Setting
+## Add Post
+
+### Set Front matter
+
+```md
+---
+title: "Getting Started"  // Post title
+category: "Instruction"   // Post category
+date: "2020-03-01 12:00:00 +09:00"  // Current time
+desc: "Let's start making blogs step by step!"  // Post desc
+thumbnail: "./images/getting-started/thumbnail.jpg" // Post thumbnail
+alt: "apple and shaking hands"  // [optional] thumbnail image alt
+---
+```
+
+- *NOTE* :  Properties other than alt must be required.
+
+## Edit About Page
+
+Easy. You can modify the `blog/about.md` file. If you need additional styling, give an id or class to a specific element in `about.md` and try to control it in the `pages/about.js` file.
+
+An example is shown below.
+
+### blog/about.md
+
+```md
+<h2 id="title">Hello</h2>
+```
+
+### pages/about.js
+
+```js
+const About = () => {
+  /* ... */
+};
+
+const Container = styled(Markdown).attrs({
+  as: 'main',
+})`
+  width: var(--post-width);
+  margin: 0 auto;
+  margin-top: 80px;
+  margin-bottom: 6rem;
+
+  @media (max-width: ${({ theme }) => theme.device.sm}) {
+    margin-top: var(--sizing-xl);
+    width: 87.5%;
+  }
+
+  h1 {
+    margin-bottom: 2rem;
+  }
+
+  h2 {
+    margin-top: var(--sizing-lg);
+
+    @media (max-width: ${({ theme }) => theme.device.sm}) {
+      font-size: 1.75rem;
+    }
+  }
+
+  h3 {
+    @media (max-width: ${({ theme }) => theme.device.sm}) {
+      font-size: 1.25rem;
+    }
+  }
+
+  /* You can Add Additional Styling here */
+
+  #title {
+    font-size: 60px;
+  }
+`;
+
+export default About;
+```
+
+## Other Customization
+
+You can freely customize each componentfile using the styled-component. If you want to change the style globally, you can change the `styles/globalStyle` file.
+
+Thank you for using `gatsby-starter-apple`. If you have any questions, please leave them on this **[link](https://github.com/sungik-choi/gatsby-starter-apple/issues).**