It started by building a frame inside using treated pine 90mmX 45mm. Fixing it to the concrete slab with dynabolts, then rafters over the top.
Stress started with gyprocking the walls, having no idea, watched a Youtube video, everything for the DIY enthusiast is on Youtube.
Though couldn't find one for a DIY vasectomy! ( My former doctor did his own using a mirror).
We lined the ceiling with limed pine boards, and in the process found the joys of the nailgun( Unfortunately Eileen has also discovered this, and everything that wasn't nailed down, is now!)
Still windows to install, flooring, etc