update README.md with Android setup instructions

README.md

@@ -16,7 +16,56 @@
 ---
 
 # Android
-_Android instructions will be added in a future commit._
+## Prerequisites
+- React Native version must be compatible with Kotlin 2.1
+  (Your host app + Gradle + Kotlin versions must match. If the native module uses Kotlin 2.1, the app must not force an incompatible Kotlin version.)
+- Java 17
+- Android Studio (includes Android SDK + Platform Tools / adb)
+
+## Running the example app (iOS)
+
+### Create and Configure the `.env` File
+
+Navigate to the example project and create the environment file:
+
+```
+cd example
+cp .env.example .env
+```
+# Example:
+
+```
+URL=https://test.webid-solutions.de
+USERNAME=your_username
+API_KEY=your_api_key
+CERT_BASE64=your_cert_base64
+# optional (only if your JS/native side uses sha pins directly)
+# SHA_PINS=sha256/AAAA...,sha256/BBBB...
+```
+
+Edit the .env file and add your username and API key.
+
+### Install Dependencies
+
+From the repository root:
+
+```
+yarn install
+```
+
+### Running the App
+
+Then navigate to the iOS example project:
+
+```
+cd example/android
+yarn start
+```
+In a second terminal:
+```
+cd example
+yarn android
+```
 
 # iOS