Update iOS.md (#361)

Author: shoumikhin

docs/iOS.md

@@ -1,15 +1,8 @@
-# iOS
+# Running LLaMA models on iOS
 
-Open the iOS Llama Xcode project at
-https://github.com/pytorch/executorch/tree/main/examples/demo-apps/apple_ios/LLaMA/LLaMA.xcodeproj
-in Xcode and click Run.  You will need to provide a provisioning
-profile (similar to what's expected for any iOS dev).
+Check out the [tutorial](https://pytorch.org/executorch/main/llm/llama-demo-ios.html) on how to build the iOS demo app running your
+PyTorch models with [ExecuTorch](https://github.com/pytorch/executorch).
 
-Once you can run the app on you device,
-1 - connect the device to you Mac,
-2 - copy the model and tokenizer.bin to the iOS Llama app
-3 - select the tokenizer and model with the `(...)` control (bottom left of screen, to the left of the text entrybox)
-
-
-Detailed step by step in conjunction with ET iOS build, to run on
-simulator for iOS.
+<a href="https://pytorch.org/executorch/main/_static/img/llama_ios_app.mp4">
+  <img src="https://pytorch.org/executorch/main/_static/img/llama_ios_app.png" width="600" alt="iOS app running a LlaMA model">
+</a>