Here you go, Bernal Diaz del Castillo's account of the conquest of Mexico, written as a soldier in Cortez' company: https://www.gutenberg.org/files/32474/32474-h/32474-h.htm
It also became clear that the Spanish, despite their superior technology, were so outnumbered that they wouldn't have been successful if it weren't for their local allies. They were nearly all killed in a desperate escape from Tenochtitlan when things went downhill.