Building Gundam models is likened to the roles of product and platform engineers, where product engineers assemble the models, and platform engineers provide the tools and infrastructure. A transition within GitHub's team from product-focused to platform engineering shifted their focus from external to internal customers, requiring new approaches in code testing and problem-solving. Key practices for platform engineering include understanding the domain, mastering network fundamentals, operating systems, infrastructure as code, and distributed systems. Knowledge sharing is emphasized for fostering innovation, preventing lost knowledge, and improving customer success. The impact radius of platform changes is significant, affecting multiple services, and it’s crucial to understand dependencies and perform postmortems. Testing changes in distributed environments like DNS is challenging, and strategies such as using test sites, Infrastructure as Code, and end-to-end testing are vital to ensure the platform's reliability and self-healing capabilities. Despite the complexities, the successful integration of these efforts results in a smoother and more efficient platform, enhancing GitHub's ability to serve developers.