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.0.com.neowizmobile.ray.google.obb'

4. Copy obb file to /SDCARD/Android/obb/com.neowizmobile.ray.google/main.0.com.neowizmobile.ray.google.obb