This crate is an example embedded project using stm32ral.
It targets an STM32F405 microcontroller but is readily adapted to other STM32 devices.
You should be able to:
$ git clone https://github.com/adamgreig/stm32ral-example
$ cd stm32ral-example
$ cargo build --release
If that didn't work, you might need to set up your Rust environment:
$ rustup target add thumbv7em-none-eabihf