hello, i think jose nava wants to know would be the workflow...
first mind, a sofa project...
then, defining the material to be used (cloths, types of foams) would be to define the skeleton (support points, which type of material to use...)
then shaping the skeleton, then shaping the foam, and then texturing the "foam", as it will also be the cloth that will cover the model.
if you do not have knowledge of complex modeling in SW, I recommend seeing tutorials about it, youtube and even here on grabcad, I believe you have a lot of material about it