AWS SAM is an open-source framework that allows developers to define their entire serverless stack, including Amazon API Gateway APIs, AWS Lambda functions, and Amazon DynamoDB tables, using a single YAML file. This approach offers several advantages such as infrastructure as code, local testing, simplified deployment, version control friendly, CI/CD integration, and more. To get started with SAM, developers need to install the AWS CLI and SAM CLI, initialize a new project, explore and modify the code, and deploy the function using the `sam deploy --guided` command. By following these steps, developers can easily deploy their Lambda functions using SAM and take advantage of its benefits for serverless development and deployment workflows.