On this link to the Valencia Government website the process is explained. Also a link to the application form, and the direct debit mandate. Some Ayuntamiento´s or local medical centres offer to process the application for you. One of the requisites to apply is to have been resident in the region for one year before application. Please note that some regions such as Murcia, Balearic Isles and Madrid do not stipulate registered residency but are using the padron as proof of the one year residency. Valencia forms mention residencia but appear to also be using the padron.
Information in Spanish
Direct Debit Mandate
Address Found on the Link ‘¿Dónde dirigirse?