Where do we begin?

Hello,

My name is Rob, my wife Perl and I are thinking about either spending winters in Spain, possibly Mijas Costa, with the possibility of eventually buying, where do we begin?

We are coming out in May for a week and to have a look around and possibly (if we can) view some property for long term rental.

With the completion of  Brexit looming, we are not sure if we could rent from December for four months and gain some form of "Residency" that we could carry forward if we do decide to buy, and poosibly move or use it in the winter and rent it in the summer.

All and any advice would be welcome.

Thanks Rob and Perl