docs: make resource fetcher documentation coherent with current code (#1001)

This PR updates the docs to match current state of resource fetcher. 

## Description

<!-- Provide a concise and descriptive summary of the changes
implemented in this PR. -->

### Introduces a breaking change?

- [ ] Yes
- [x] No

### Type of change

- [ ] Bug fix (change which fixes an issue)
- [ ] New feature (change which adds functionality)
- [x] Documentation update (improves or adds clarity to existing
documentation)
- [ ] Other (chores, tests, code style improvements etc.)

### Tested on

- [ ] iOS
- [ ] Android

### Testing instructions

<!-- Provide step-by-step instructions on how to test your changes.
Include setup details if necessary. -->

### Screenshots

<!-- Add screenshots here, if applicable -->

### Related issues

<!-- Link related issues here using #issue-number -->

### Checklist

- [ ] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have updated the documentation accordingly
- [ ] My changes generate no new warnings

### Additional notes

<!-- Include any additional information, assumptions, or context that
reviewers might need to understand this PR. -->

Author: chmjkb

.cspell-wordlist.txt

@@ -180,3 +180,4 @@ nˈɛvəɹ
 ˈɛniwˌʌn
 ˈɛls
 Synchronizable
+stringifying

docs/docs/01-fundamentals/01-getting-started.md

@@ -38,32 +38,59 @@ For supported React Native and Expo versions, see the [Compatibility table](../0
 
 ## Installation
 
-Installation is pretty straightforward, just use your favorite package manager.
+Installation is pretty straightforward, use your package manager of choice to install the package and some peer dependencies required to streamline model downloads. If you want to implement your custom model fetching logic, see [this document](../08-resource-fetcher/02-custom-adapter.md).
 
 <Tabs>
   <TabItem value="npm" label="NPM">
 
     ```
     npm install react-native-executorch
+    # For Expo projects
+    npm install react-native-executorch-expo-resource-fetcher
+    # For bare React Native projects
+    npm install react-native-executorch-bare-resource-fetcher
     ```
 
   </TabItem>
   <TabItem value="pnpm" label="PNPM">
 
     ```
     pnpm install react-native-executorch
+    # For Expo projects
+    pnpm install react-native-executorch-expo-resource-fetcher
+    # For bare React Native projects
+    pnpm install react-native-executorch-bare-resource-fetcher
+
     ```
 
   </TabItem>
   <TabItem value="yarn" label="YARN">
 
     ```
     yarn add react-native-executorch
+    # For Expo projects
+    yarn install react-native-executorch-expo-resource-fetcher
+    # For bare React Native projects
+    yarn install react-native-executorch-bare-resource-fetcher
     ```
 
   </TabItem>
 </Tabs>
 
+:::warning
+Before using any other API, you must call `initExecutorch` with a resource fetcher adapter at the entry point of your app:
+
+```js
+import { initExecutorch } from 'react-native-executorch';
+import { ExpoResourceFetcher } from 'react-native-executorch-expo-resource-fetcher';
+// or BareResourceFetcher for Expo projects
+
+initExecutorch({ resourceFetcher: ExpoResourceFetcher });
+```
+
+Calling any library API without initializing first will throw a `ResourceFetcherAdapterNotInitialized` error.
+:::
+
 Our library offers support for both bare React Native and Expo projects. Please follow the instructions from [Loading models section](./02-loading-models.md) to make sure you setup your project correctly. We encourage you to use Expo project if possible. If you are planning to migrate from bare React Native to Expo project, the link (https://docs.expo.dev/bare/installing-expo-modules/) offers a guidance on setting up Expo Modules in a bare React Native environment.
 
 If you plan on using your models via require() instead of fetching them from a url, you also need to add following lines to your `metro.config.js`:
@@ -89,7 +116,7 @@ Because we are using ExecuTorch under the hood, you won't be able to build iOS a
 Running the app with the library:
 
 ```bash
-yarn run expo:<ios | android> -d
+yarn <ios | android> -d
 ```
 
 ## Supporting new models in React Native ExecuTorch