The custom resource in this example is a Greetings resource with one property: Greeting text. The text will later be displayed in the Outputs section of your stack.
The function code is the file index.js is for reference only. For simplicity, the code of the function is in the template.
Use deploy.sh to deploy your stack. Note that the CLI command has timeout-in-minutes option - this is to prevent having to wait ~1h for CloudFormation to start rollback if the custom resource could not be created (for instance: due to lambda errors).