This crate requires a nightly (unstable, experimental) compiler version. To switch to it, you must have Rust installed via Rustup, and run:
rustup default nightly
Run rustup default stable to switch back.
Adding pwasm_std library as a dependency
Run this command in a terminal, in your project's directory:
cargo add pwasm-std
To add it manually, edit your project's Cargo.toml file and add to the [dependencies] section:
pwasm-std = "0.13.1"
The pwasm_std library will be automatically available globally.
Read the pwasm_std library documentation.