AWS Step Functions allows users to build applications by connecting AWS services into cohesive workflows, using a state machine diagram to illustrate the connections between services. The text provides a detailed walkthrough of creating a simple application using AWS Step Functions, including setting up a Lambda function, IAM roles, and policies, and deploying the workflow using Pulumi. Initially, a "Hello World" function is created and executed, demonstrating the basic setup process. The guide then expands by adding an additional step with a new function that returns "Nice to meet you," showcasing how to update the state machine to include multiple steps. Pulumi's programming model is highlighted, particularly its handling of resource outputs and dependencies. The article serves as an introductory guide to AWS serverless workflows, with hints at further expansion possibilities using custom Lambda functions and additional AWS services, and mentions that the example is also available in TypeScript for those who prefer a different programming language.