There are 4 parts to the citizenship interview. (1) Questions about your N-400 form; (2) 10 questions of the 100 Civics Questions (see recommended books on this page); (3) Reading a sentence in English; (4) Writiing a sentence in English.
If you want to become a citizen, the USCIS (formerly INS) video above will help you understand what you need to do.
