On the second leg of this trade slaves were transported to the West Indies, this leg was called the middle passage. This part was horrible for the slaves. About 50% of all the slaves on one ship would not make it to the West Indies because of disease or brutal mistreatment. Hundreds of men, woman and children were cramped together for most of the journey, occasionally able move an almost decent amount.
On the third leg of the journey slaves were traded for sugar, molasses and other products. Those products were shipped to Europe or other European colonies in the Americas. The slaves in the West Indies were then sold to whomever wanted to buy some. After this whole process the cycle repeated itself over and over, and this system was used for a long time.
To supply the thirteen colonies effectively though trade, Europe came up with the idea of triangular trade. Africa, the 13 colonies, and Europe were part of Europe's invention of triangular trade. In all,