What are the relevant force calculations in the design of a manually operated metal sheet shearing device?

I am undertaking a project in mechanical engineering with the title, 'design and development of a manually operated metal sheet shearing device for small scale fabrication purposes'. I need info on the relevant force calculations to be considered in this design. Such information may include shear force calculations, load on bearings if any, metal sheet thickness to be considered e.t.c. My final solution was a hand operated shear operating through the transmission of force by a coupling. The force is transmitted to the shearing section. I have no idea of the magnitudes of force required such as the cutting force or the force distribution in the mechanism's framework. Any kind of istance would be greatly appreciated.