Kostas Vilkelis overhauled the ADA HPC cluster documentation in the ubvu/open-handbook repository, focusing on improving onboarding and user guidance for cluster users. He consolidated and reorganized content related to software access, login procedures, SLURM usage, hardware details, Open OnDemand, and help resources, resulting in a more navigable and user-friendly documentation structure. Using Markdown and Shell, Kostas applied disciplined editorial changes to enhance consistency, clarity, and usability, including refined headers and login instructions. The work culminated in a comprehensive first draft with clear author attribution, providing a solid foundation for future updates and supporting more efficient onboarding for new users.