You may need to press the zoom extents button to view the data. However, printing in AutoCAD is based on ISO paper sizes using millimetres so in order to print at a specific scale you need to convert the model from metres to millimetres.
The instructions below explain how to re-scale a drawing from metres to millimetres. AutoCAD typically deals in millimetres, but Ordnance Survey data available in Digimap is provided in metres.