Grant44 wrote:
Hi, im stuck for how to model this design (photo of sketch attached). I have never tried creating something like this on the pc so any help would be great, thanks.

Take a look at OBJECTiVE. It's free to use with the educational version of ArchiCAD (no registration required). You can create profiled shapes, bend them to curves, and offset the end to rise along the curve. See the attached image of a stair under construction with these tools.