docs: update quick start

Author: zhiwen.zhao

docs/getting-started.md

@@ -6,4 +6,56 @@ nav:
 
 # 快速上手
 
-Balabala...
+## 安装
+
+**使用 npm 或 yarn 安装**
+
+```shell
+$ npm install @zzzzw/happy-ui --save
+```
+
+```shell
+yarn add @zzzzw/happy-ui
+```
+
+## 示例
+
+```js
+import Alert from '@zzzzw/happy-ui/es/alert'; // 手动按需加载 js
+import '@zzzzw/happy-ui/es/alert/style'; // 手动按需加载 less
+
+ReactDOM.render(<Alert kind="warning">这是一条警告提示</Alert>, mountNode);
+```
+
+### 自动按需加载
+
+使用 [babel-plugin-import ](https://www.npmjs.com/package/babel-plugin-import) 优化引入方式，如下：
+
+```js
+import { Alert } from '@zzzzw/happy-ui'; // 与上述示例等价
+
+ReactDOM.render(<Alert kind="warning">这是一条警告提示</Alert>, mountNode);
+```
+
+安装 `babel-plugin-import`
+
+```
+yarn add babel-plugin-import --dev
+```
+
+配置`.babelrc` 或 `babel-loader`
+
+```json
+{
+  "plugins": [
+    [
+      "import",
+      {
+        "libraryName": "@zzzzw/happy-ui",
+        "libraryDirectory": "esm", // default: lib
+        "style": true // or 'css'
+      }
+    ]
+  ]
+}
+```