doc/docs/en/shared/bundle-resources.md

Bundle resources are additional files and folders located as a part of your application bundle using the Bundle Resources field in game.project.

The Bundle Resources field should contain a comma separated list of directories containing resource files and folders that should be copied as-is into the resulting package when bundling. The directories must be specified with an absolute path from the project root, for example /res. The resource directory must contain subfolders named by platform, or architecture-platform.

Supported platforms are ios, android, osx, win32, linux, web, switch A subfolder named common is also allowed, containing resource files common for all platforms. Example:

res
├── win32
│   └── mywin32file.txt
├── common
│   └── mycommonfile.txt
└── android
    ├── myandroidfile.txt
    └── res
        └── xml
            └── filepaths.xml

You can use sys.get_application_path() to get the path to where the application is stored. Use this application base path to create the final absolute path to the files you need access to. Once you have the absolute path of these files you can use the io.* and os.* functions to access the files.