Added build instructions to README.

Change-Id: I0bada6db974d390bfc154f125c0e0428c1d427a7

README.md

diff --git a/README.md b/README.md
index 82c6504..f5c2e3c 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,28 @@
 Dawn is an open-source and cross-platform implementation of the [WebGPU](https://webgpu.dev) standard.
 More precisely it implements [`webgpu.h`](https://github.com/webgpu-native/webgpu-headers/blob/main/webgpu.h) that is a one-to-one mapping with the WebGPU IDL.
 
+
+### Building
+Samples
+
+- Clone the repository locally.
+- Fetch the dependencies using `python tools/fetch_dawn_dependencies.py`
+- Compile using Cmake+make
+```sh
+mkdir -p out/Debug
+cd out/Debug
+cmake ../..
+make # -j N for N-way parallel build
+```
+
+Android Samples
+
+- Clone the repository.
+- Fetch the dependencies using `python tools/fetch_dawn_dependencies.py`
+- Open src/samples/android in Android Studio Flamingo 2022 or greater.
+- Build and run any of the samples on a physical Android device.
+
+
 ## License
 
 BSD 3-Clause License, please see [LICENSE](/LICENSE).