The tutorial builds on previous knowledge of API testing with Postman by introducing the use of the Newman CLI tool to generate detailed and storable reports for API tests. It outlines prerequisites such as basic JavaScript knowledge, a Postman desktop installation, and accounts with CircleCI and GitHub, along with a Node.js setup. The process involves synchronizing Postman collections, creating a local project using Newman and the newman-reporter-htmlextra package, and running API tests to produce reports. The tutorial further extends to automating this report generation using CircleCI, by setting up a configuration file to automate the test runs and report generation upon each update to the API code. This automation ensures that the test reports are generated and stored as artifacts in the CircleCI environment, thus enhancing the efficiency and accessibility of the testing process.