Create a new project with cargo init --bin and add the following to your Cargo.toml file.

See the example code in GitHub.

Rust doesn't prescribe any particular structure for your project's layout on the end user's device filesystem. The following is one recommendation

The rust compiler is natively capable of cross-compiling for a wide range of targets. You will need to configure a local .cargo/config.toml file in the root of your project directory to provide the necessary rustc, linker, and potentially C compiler arguments. For most targets you will need to provide an alternative sysroot for your target (not host) platform, often exposing a POSIX C library, header files, binutils, and a linker.

The Ditto SDK build.rs script failed to download an appropriate ditto binary for your target platform. Look at the build script's log at target/<profile>/build/dittolive-ditto-sys-<hash>/stderr for any errors.

Check your internet connection is live and Ditto version number is correct. Inspect the downloaded library in the cargo build cache (default is target/<profile>/build/dittolive-ditto-sys-<hash>/out/libdittoffi.{a,dylib,so,dll}) using your platforms utilties such as file, otool, readelf or similar. Try updating to the latest release of dittolive-ditto. You can also manually download the binary yourself.