I've recently read Martim Afonso's brother's journal about his journey to Brazil in 1531, and since then, I've been looking for resources on how these expeditions were and the daily life of a conquistador/explorer. I.e. How did they camp? What did they wear/carry? How did they organize and plan their routes? How did they manage their supplies? What did they eat?
It could be anything from 15th to 17th century, I'm really interested in this topic and I'd love to discover more about it.
I would recommend you read the memoirs of Alvar Núñez Cabeza de Vaca, aptly titled "Shipwrecks". More literature on the conquistadores, by the conquistadores themselves, include "True history of the conquest of the New Spain", by Bernal Díaz del Castillo, Hernán Cortés' own "Cartas de relación", and Gonzalo Fernández de Oviedo's "General and Natural History of the Indies", as well as his "History of Nicaragua".
There are many records too, from other conquistadores, giving detailed explanations about their expeditions, normally in order to try to get some benefits (captaincies, lands, titles, offices, whatnot). The General Archive of Indies has a lot of such reports, normally called "memorial de servicios" or "méritos".
Have a look at Portal de Archivos Españoles where there are many of those memorials already digitalised.