%
%  Chapter 1
%  
%  
%  
%  
%
\chapter{Chapter Title}
\label{ch1}
% the label lets you refer to the chapter by number later.

Talk a little.

\section{Section Title}
\label{s1.1}

Talk some more.

\subsection{Subsection Title}
\label{ss1.1.1}

Be specific.

% if you want a subsection, but with no number
\subsection*{Numberless Subsection} 

% you have to manually add it to the table of contents
\addcontentsline{toc}{subsection}{Numberless Subsection} 
\label{ss1.1.2}

\section{Another Section Title}
\label{s1.2}

Talk it up.

% you can do the same with sections, just * them and add them to the contents if you want.