Barn renovation wood structural calcs and drawings

I need some structural designwork an calculations for the upper structure of our barn renovation. The downstairs structure is all blockwork (stone clad on the outside). The upper structure is timber frame and floor, with a timber roof. The complete upper structure is to be covered in zinc. Recommendations of which timbers to use etc in line with UK building regs

I already have some basic structural drawings etc to give an idea of whats required. Will attach following your reply.