You need an active AWS account. You need to follow the section Getting started in the recipes Your first AWS Lambda and Your first Lambda with AWS CLI from Chapter 1, Getting Started with Serverless Computing on AWS to set up Java, Maven, the parent project, serverless-cookbook-parent-aws-java, and AWS CLI, and may also read other notes there including code usage guidelines, S3 bucket creation, and notes for Windows users.

As we are reusing the Lambda that we used in the recipe Building your first API with Lambda integration, you will need to build and deploy that Lambda (if you have not done so already). You can follow the steps in that recipe to build the project and upload JAR to S3, and you can use the provided CloudFormation template to deploy the Lambda.

The body mapping templates are written based on VTL and JSONPath expressions. So, having a decent understanding of the Apache VTL language and JSONPath expressions will help you to better understand the sample templates and to develop templates that suit your project's needs.