I need to work with census data and don't know where to start.
There are a number of resources you can use to learn about and use census data. The ISSR Data Archive maintains a collection of census data covering many years and countries.
http:https://www.sscnet.library.ucla.edu/issr/da/catalog.htmsocial-science-data-archive/about-data-archivehttp://www.sscnet.ucla.edu/issr/da/index/techinfo/M7891.HTM
The Census Bureau provides options for making tables and downloading reports, maps and tables.
http:https://www.data.census.gov/main/www/cen2000.htmlcedsci/
Other useful census data sites:
http:https://www.ats.guides.library.ucla.edu/stat/census/census