This is where we start to get our hands dirty. CloudFormation template files are the codified representations of your stack and are expressed in either YAML or JSON. When you wish to create a CloudFormation stack, you push a template file to CloudFormation through its API, web console, command-line tools, or some other method (such as the SDK).

Templates can be replayed over and over again by CloudFormation, thus creating many instances of your stack.