I am trying to understand what congress cannot do, but its confusing.

Answer 1

Check Section 9 of Article I.

http://www.law.cornell.edu/constitution/constitution.articlei.html

Answer 2

Thanks for the link, however, It is very hard to understand. Do you know where I can find it in kids terms?

Answer 3

See if this site helps you understand this article.

http://www.usconstitution.net/xconst_A1Sec9.html

This site gives a short overview
http://caselaw.lp.findlaw.com/data/constitution/article01/45.html#1

Answer 4

Thanks the summary was a great help!