Add subsection about adding new models to RNE ecosystem (#779)

## Description

As in the title

### 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

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### Screenshots

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### Related issues

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### Checklist

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

### Additional notes

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Author: msluszniak

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

@@ -90,6 +90,16 @@ Running the app with the library:
 yarn run expo:<ios | android> -d
 ```
 
+## Supporting new models in React Native ExecuTorch
+
+Adding new functionality to the library follows a consistent three-step integration pipeline:
+
+1. **Model Serialization:** We export PyTorch models for specific tasks (e.g., object detection) into the *.pte format, which is optimized for the ExecuTorch runtime.
+
+2. **Native Implementation:** We develop a C++ execution layer that interfaces with the ExecuTorch runtime to handle inference. This layer also manages model-dependent logic, such as data pre-processing and post-processing.
+
+3. **TS Bindings:** Finally, we implement a TypeScript API that bridges the JavaScript environment to the native C++ logic, providing a clean, typed interface for the end user."
+
 ## Good reads
 
 If you want to dive deeper into ExecuTorch or our previous work with the framework, we highly encourage you to check out the following resources: