Heat is the main project in the OpenStack Orchestration program. It implements an orchestration engine to launch multiple composite cloud applications based on templates in the form of text files that can be treated like code.
Start understanding how Heat fits into OpenStack by reading the architecture guide. Next, download and install the Python command line clients.
Then, for a simple guide to getting started with developing templates for Heat you can check out the tutorials on the OpenStack documentation site.
Finally, follow the instructions for creating PNDA on OpenStack.