Hi,
Nice idea.
Where to start? well you need to start with your brief. What you want from your move, what sort of property do you want, ie bedrooms, facilities, close to shops or beach or golf or what ever. What will it cost, property plus the legal costs - about 14% of purchase price.
Then start your research into life in Spain, this site will give you lots of information, so use it, store it and add it to other information to make your picture. Research the cost of property to meet your brief, if you can not find something that meets the cost brief, look in other places, but keep the information you have on your first area.
Buy a map, cross off the area’s you do not want or outside your price range, then concentrate on the area’s that are left. When you are down to just a few, then tighten up on your brief and amend your brief to allow to find somewhere, then when you are happy with what have, go out and look around, get to know the area, go back home and think about it.
A locator is a nice thing to have, but some of the fun of the project is doing it. Then find someone who will assist you to find what you want to meet your brief, most will do that for free as they work on commission, so use the service. Ask on here for advice, you will get it for free much of it from those who have aready done what you are looking to do.
Good luck
Dave