[docs] Add Router API reference

docs/pages/versions/unversioned/sdk/router.mdx

@@ -8,12 +8,40 @@ platforms: ['android', 'ios', 'web']
 
 import APISection from '~/components/plugins/APISection';
 import { APIInstallSection } from '~/components/plugins/InstallSection';
-import { SnackInline } from '~/ui/components/Snippet';
+import { ConfigPluginExample } from '~/components/plugins/ConfigSection';
+
+`expo-router` is a routing library for React Native and web apps. It enables navigation management using a file-based routing system. It provides native navigation components and is built on top of [React Navigation](https://reactnavigation.org/).
 
 ## Installation
 
-<APIInstallSection packageName="expo-router" />
+<APIInstallSection packageName="expo-router" hideBareInstructions />
+
+## Configuration in app.json/app.config.js
+
+If you are using the default template to create a new project, `expo-router` [config plugin](/config-plugins/introduction/) is configured in the app config.
+
+<ConfigPluginExample>
+
+```json app.json
+{
+  "expo": {
+    "plugins": ["expo-router"]
+  }
+}
+```
+
+</ConfigPluginExample>
+
+## Usage
+
+{/* TODO:(@aman) To update the following once https://github.com/expo/expo/pull/28804 is merged which offers instructions for basic usage. */}
+
+Find more information and guides about using `expo-router` in [Expo Router](/router/introduction/) section.
 
 ## API
 
+```js
+import { Stack, Tabs, Link } from 'expo-router';
+```
+
 <APISection packageName="expo-router" />