After google released the API to be able to implement maps, with the cartography and functionalities of googlemaps, various tutorials have emerged. This is one of the most complete; This is Mike Williams' page that starts from the basics, then some advanced techniques, and finally map customization, including extensions and third-party developments.
Very complete Mike's page, although of course, is in English.
… The image? Yes, it is a conceptual sketch of Google maps, which one day I had to do to explain to some GIS smokers, of those who also smoke from the green.