1. Download APK first, then copy to your Android device's SD card

2. Install APK, DO NOT open app

3. Download obb files, then rename to 'main.218.com.extremedevelopers.battleofhelicopters.obb'

4. Copy obb file to /SDCARD/Android/obb/com.extremedevelopers.battleofhelicopters/main.218.com.extremedevelopers.battleofhelicopters.obb