## Working on an Existing Cargo Package

If you download an existing package that uses Cargo, it’s really easy to get going.

First, get the package from somewhere. In this example, we’ll use `regex` cloned from its repository on GitHub:

    $ git clone https://github.com/rust-lang/regex.git
    $ cd regex

To build, use `cargo build`:

    $ cargo build
       Compiling regex v1.5.0 (file:///path/to/package/regex)

This will fetch all of the dependencies and then build them, along with the package.