When Napoleon first arrived, he was greeted with bow and arrows pointed at him. The tribe had just had a raid on their women and were kidnapped.
After denying the Yanomamo of what they wanted, a few of the members cut Napoleon's canoes and had them float down stream. He then scolded the culprits and was praised by the rest of the village.
Napoleon discovered that the Yanomamo value sharing very much in the society. When he would not give them anything, they would surround his shelter and sometimes steal what they wanted.
After dealing with this behavior of the Yanomamo, Napoleon decides to stand up to them and become more aggressive to gain more respect from the people in the tribe. They are saddened but now do not bother him anymore for stuff they want from him, nor do they try to steal.
When Napoleon first arrived at the camp, he discovered how the people of the tribe rely on drugs to communicate with the spirit world. And when he first got there, they had large wads of drugs under their lower lip and mucus dripping from their noses.
Napoleon also quickly learned how members of the tribe sleep and live under one large communal structure, where they sleep in hammocks and take hallucinogenic drugs together in order to contact the spirit world.