All assets for native apps, ‘pure’ or not, should be stored in the “assets” folder in the project directory on the same level as the “jni” folder. Then the Android build system knows to include them in the app apk file.
The folders in the VisualGDB project do not necessarily reflect the folders on the harddisk and are just used to visually group the existing files.
Thus you can add the asset files in the Resources folder to easily edit them from Visual Studio, but they need to physically be in the “assets” folder in the project directory.