The king and queen of Spain were kicked out of the Silk Road Trade Route so when Christopher Columbus set out to go west they were on board.
With the technology that the Europeans had, they could travel the seas much more efficiently. After a few weeks on the sea, they finally found "India" and set course to trade.
After figuring out that the Natives weren't Indians, he imminently set out to use them for Gold and Glory. They also traded things like Cows and Wheat for Turkeys and Tabacco, but that isn't all they traded.
After trading and using the inhabitants as slave the unintended consequence was the trade of the Europeans diseases killing millions of Native Americans, introducing the begining of African Slaves.
Once people shipped Africans in small uncomforable ships, that changed the world for the worse and better with millions of people dead and better diets for the rest of the world.