The Inca Empire stood no chance against the Spanish conquistadors, being about a thousand years behind them in technology.
I suggest The Discovery and Conquest of Mexico, by Bernal Diaz. He was a foot soldier who fought through the whole conquest with Cortez.
https://freerepublic.com/focus/f-bloggers/4224656/posts
That was the Aztecs. Incas lived in South America. Aztecs Mayas and Toltecs lived in Central America and Mexico. Aztecs were the ones who did human sacrifice taking the hearts out of living people while they were still beating. They were savage.