Download the hawk-lang binary for your platform, or compile from source by running cd app && cargo build --release. If built from scratch, the binary can be found in app/target/release. Copy the downloaded or compiled binary to a folder that is in your PATH and make sure it works by running hawk-lang.
Create a .hawk file to write your code in and run it with hawk-lang filename.hawk, or use the shell by running hawk-lang.
The syntax of the Hawk language can be found in spec.md, and documentation of the standard library in std.md.