Emanuele Vitali enhanced the Lumi-supercomputer/lumi-userguide repository by revising the Singularity container documentation to clarify PRoot-based build options. Focusing on developer onboarding and user guidance, Emanuele improved the Containers page by providing detailed explanations and practical examples for PRoot-based container builds. The work emphasized clear technical writing and thorough documentation practices, using Markdown to ensure readability and accessibility. By addressing ambiguities in containerization workflows, Emanuele enabled users to better understand and deploy Singularity containers on the Lumi platform. The contribution demonstrated depth in containerization and documentation, resulting in a more robust and user-friendly resource for the developer community.