All of the Rocket z/OS ports of open source languages and tools are available for download from the Rocket Community website downloads page.
Log in to the Rocket Community here: https://my.rocketsoftware.com/RocketCommunity/RCLogin
If you do not have an account, you can request one here at no cost.
All downloads are meant to be unpacked on z/OS. However, most people first download to a PC and then transfer to z/OS (e.g. via SFTP) for unpacking. Be sure to use binary mode when transferring!