The reasons for the Chinese moving to the U.S. is due to crop failure (which lead to hunger)...
...and over population in their home land
Many Immigrants traveled by steerage, (lower deck of ships), where lots of people stayed for long periods of time during the voyage. Many became ill and died before making it to America.
The remaining immigrants settled West, mainly around California. There, many of them got jobs as miners or opened up their own restaurants, shops and, laundries.
However, the Chinese were hated by Americans. They were treated terribly and forced out of their jobs/mining because of social and government thoughts towards them. The whole reason why they immigrated in the first place was to have a better life, but they ended up being treated, basically, the same as they were in their home country.