currently, staple provide two ways to download its stable binary version. for those who is using rust can download it via Cargo:
cargo install staple
or, you can download the latest version in Github Release.
if you really need a developer version to taste some new feature which are not stable yet at the first time, you can download the latest staple code and compile it via Cargo:
cargo install --git https://github.com/Kilerd/staple.git