They were structured like a military camp- with a few exceptions because they were harboring civilians and needed to replicate a functioning community. They layouts were formatted in square sections, dividing blocks Families, bachelors, and orphans lived in tar paper barracks which were not insulated with a couple of belly pot stoves. They ate at mess halls, had latrines and laundry facilities which were placed at each square footage of blocks. As the camps progressed, fire stations, hospitals, newspapers, schools, and some local businesses were added. Community and social events were vital in persevering moral. Dances, creative classes, educational classes, and sports flourished.
Although the military police overlooked the camps up in the watchtowers, and although the camp directors with other higher authorities in camps were white, security police were Japanese-American. Other political positions were held by the Japanese-Americans who handled the organization of the camps which included labor unions, farming, and other essential social aspects. Only the young adults with American citizenships were allowed to hold these positions; excluding their fathers who many use to be community leaders themselves. They were forbidden.
This is just a broad overview and each camp was a little different based on location and who ran the camps. Some had more liberty freedom than others, such as they were allowed to take photos of the camps; other camps were divided into further segregation and discord.
For more information, these are good resources:
Tateishi, John. And Justice for All: An Oral History of the Japanese American Detention Centers. New York, New York: Random House, 1984.
Gesensway, Deborah and Roseman, Mindy. Beyond Words: Images from America's Concentration Camps. Ithaca, New York: Cornell University Press, 1987.
Weglyn, Michi. Years of Infamy: The Untold Story of America's Concentraion Camps. New York: William Morrow and Company. 1976.
Answers.com (answered by K.P. Kollenborn, historian)