People would want to live the American Dream because of what they are told and promised in their homeland. For example, (I'm not sure when) but immigrants back then would be so excited to go to America because they were told the roads were paved in gold. Most importantly, these people came from countries going through war, famine, discrimination against certain minorities, and other hardships. They came to America to live in America because of the promise of freedom, and that's all they wanted.
I'm guessing this is for NHD, I worked on that too.
One tip is to find a trusty database such as history.com and find articles on the person. These are secondary sources. Another great secondary source is going to your library and getting books on the person.
To find primary sources, look for good pictures of Barbara Kingsolver.
Did she write any speeches or does she have any quotes? These are primary sources.
Hope this helped!