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.

It would be good to first go through the Using the DynamoDB SDK from Lambda recipe to understand the theory behind using the AWS SDK for DynamoDB from Lambda. Otherwise, refer back to that recipe whenever you have doubts. It is also assumed that you have decent knowledge of Java and Maven.