Sorry I would like to make a power so that I can close in the future in Spain I have to have an appointment with you and I have to register my son and I also have to have an appointment

If it's a power of attorney before you have to fill out a form by e-mail and explain to them why you want the power of attorney and they will tell you the requirements you need and they give you the appointment themselves. http://www.exteriores.gob.es/Consulados/NUEVAYORK/en/ServiciosConsulares/Paginas/Actos.aspx

It is not necessary to have an appointment to go. But it is recommended that you go early at about 8.30 am.