You must install Python, PostgreSQL, Redis, and Node.js before going any further.

Refer to the documentation of Python (2.7), PostgreSQL (9.3 or newer), Redis (2.8.3 or newer), and Node.js (v6 or newer) to learn more about how to install them in your environment. On macOS, you can use brew to install them. On Linux, you can use your package manager (yum/apt-get); just make sure it installs the aforementioned versions.