Maybe you should read the The Conquest of Florida by Hernando de Soto (1541) you can find his actual diary notes and letters in spanish or some book adaptation

Maybe you should read the The Conquest of Florida by Hernando de Soto (1541) you can find his actual diary notes and letters in spanish or some book adaptation in english as the one from Theodore Irving. For the spanish settling in america was mostly setting ties and allies with native populations, often as exchange of technology or accepting to fight against a local historical enemy from the communities. You might also find interesting the biography of Don Juan de Onate, also named "the last Conquistador" who dominated the whole south of nowadays USA and built communities, ended up civilizating the zone, etc.