The Columbian Exchange started when Columbus got to the New World. He brought various items with him from Europe to exchange with the Native Americans. Because of this, things from the Old World were brought to the New World and vice versa.
Many things were exchanged during this time, like plants, animals, slaves, items, and diseases.
One of the first diseases brought to the New World was syphilis. This disease was not native to North America and came from the Old World because one of the people going there had it, and it spread to the natives.
African slaves were also introduced to North America because the landowners there needed a cheap labor force to produce sugar, tobacco, and other “cash crops”.
Speaking about cash crops… Sugar, coffee, and wheat were all introduced from the Old World and grew quite well. Potatoes, maize (corn), tomatoes, and tobacco were all imported from North America. For example, potatoes were important to the Old World because they could grow basically anywhere and provided food for many poor people.
South America became a large producer of silver for the Old World since it had large deposits of the valuable mineral in the ground there. Furthermore, the wheel was introduced to the New World, which made transporting said silver, as well as basically anything else much easier.
I think that the Columbian exchange was good for all the areas which it affected, although probably better for the people living in the Old World, as they had better immunity to the diseases that they brought to the New World.