There's many commands available to format your text.
The structure looks like this:
\part, \chapter, \section, \subsection, \subsubsection, \paragraph
and \subparagraph; \part and \chapter are not available
in the article style.
The command \tableofcontents automatically makes the table of
contents. The headlines for the different levels must be in brackets after
the command, e.g.
\section{Two Roman fortresses in Gallia}
\subsection{Laudanum}
\subsection{Aquarium}