The built-in headings will be included in the TOC by default; therefore it is convenient for you to make use of them. You can modify their formatting if you want to. The basics on TOC creation is explained in the article at
http://www.shaunakelly.com/word/numb...fcontents.html.
To prevent other paragraphs from being added into the TOC, deleting the \u switch from the TOC field code is the easiest way. Take a look at
http://word.mvps.org/faqs/general/DocumentMap.htm.