During May 2025, Kim SeongHyun contributed to the se-sac/sesac-01 repository by creating and updating documentation to support class homework onboarding. He developed two README.md files for the class01 and class02 homework directories, focusing on initializing and stabilizing class records. Using Markdown, Kim SeongHyun ensured that student information, particularly entry '02', was accurately reflected in both files, thereby improving data integrity and onboarding readiness. His work centered on documentation skills and careful data correction rather than code or bug fixes, providing foundational support for future development. The scope was focused and addressed essential setup for class record management.