This comprehensive tutorial guides users through the process of setting up an autoscaling CircleCI self-hosted runner infrastructure using AWS Cloud Development Kit (CDK), which facilitates the deployment and management of AWS resources through Infrastructure as Code (IaC). It provides a step-by-step approach, including prerequisites such as installing necessary tools and creating AWS and CircleCI accounts. Users learn to define an AWS Lambda function for autoscaling, configure EC2 instances with a startup script, and secure credentials using AWS Secret Manager. The tutorial covers creating a CircleCI project, configuring CI/CD pipelines, and automating deployments with CircleCI, emphasizing the benefits of autoscaling for optimizing costs and meeting fluctuating resource demands. Additionally, it explains how to test the setup with a NodeJS application and highlights the advantages of using AWS CDK for provisioning resources with familiar programming languages and object-oriented techniques.