As in many novels, the social mores, codes, and conventions of the era are on display in the narrative. From styles of dress and comportment to modes of speech, people are presented in various culturally specific ways. Most notable in this novel, the values of the time are explored to significant effect.
The values of the time, as expressed through socially mediated perceptions, honored people of some skin colors over others. Also, wealth and class were issue that seemed more intractable than today, though the distance between wealth and poverty in the antebellum era is not as wide as it is today.
Characters like Pap Finn and Tom Sawyer help to articulate the thoughts and beliefs of the era.
There are numerous ways. Did you feel like you understood the antebellum south more after you finished reading the book?