Harpsichord, Clavichord for sale - Courteous ask of informations

I don't understand so well what is here in question.
I'm not trying to purchase anything. Being, otherwise, interested in knowing something (or all of the difficult art of building harpsichords et relata, materials involved and so on, I would like to ask you any information about the chance of getting from yo (or from other people) any detailed plan about this. If possible, please, tell me it just to preview the prices/costs of this operation. In any case, any other information on the subject will make me very happy.
Many thaks. With my Best regards - Pierluigi Pollini