You must apply for a NLV from your home country, not in Spain.
BLS Spanish visas handle all applications and you can check on their site what is required and which consulate will deal with it.
Just enter your country and your county and they will link you to the correct consulate. You need an income of €28,800 for the first applicant and €7,200 for the second and subsequent ones. You require medical care which can be a private health policy or public provided if you are over pensionable age and receiving a state pension with an S1.
Decisions are made within 2 months but it can take longer than that if there is anything that needs confirming or shorter if it goes through.. You need a medical certificate stating you have no communicable diseases and a police records check. The BLS site shows you what you need and the consulate site will show you how to get them and how to translate everything to Spanish which is required. Translations must be officially apolstilled and not Google tranlsated.
Renewal after the first year is exactly the same as the initial one but from Spain. Year 2 must show double the required income to last for 2 years.
Once it has been approved, the time to move to Spain and apply for residency has been extended to one year.
Best of luck.