Talk Quesada forum

Go to your nearest Suma office and register for a Cl@ve. You can select the cl@ve option for an appointment from the drop down menu.
https://www.suma.es/cita_previa.xhtml

You can request one at Town Halls as well. Not sure if all of them do it.
A helpful guide from AEAT

https://sede.agenciatributaria.gob.es/S ... t-csv.html

Bee

There´s a DIY guide on Costa Blanca Forum:

https://www.costablancaforum.com/area/f ... ro-163806/

Thank you Bee and Paulr