\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amssymb}

\begin{document}

List are really easy to create
 
\begin{itemize}
\item One entry in the list
\item Another entry in the list
\end{itemize}

\section{Unordered lists}

\begin{itemize}
\item The individual entries are indicated with a black dot, a so-called bullet.
\item The text in the entries may be of any length.
\end{itemize}

\section{Ordered lists}

\begin{enumerate}
\item The labels consists of sequential numbers.
\item The numbers starts at 1 with every call to the enumerate environment.
\end{enumerate}

\section{Nested Lists}

\begin{enumerate}
 \item The labels consists of sequential numbers.
 \begin{itemize}
 \item The individual entries are indicated with a black dot, a so-called bullet.
 \item The text in the entries may be of any length.
 \end{itemize}
 \item The numbers starts at 1 with every call to the enumerate environment.
\end{enumerate}

\section{Lists styles}

\subsection{Ordered lists}

\begin{enumerate}
 \item First level item
 \item First level item
 \begin{enumerate}
 \item Second level item
 \item Second level item
 \begin{enumerate}
 \item Third level item
 \item Third level item
 \begin{enumerate}
 \item Fourth level item
 \item Fourth level item
 \end{enumerate}
 \end{enumerate}
 \end{enumerate}
 \end{enumerate}
 
 \renewcommand{\labelenumii}{\Roman{enumii}}
 \begin{enumerate}
 \item First level item
 \item First level item
 \begin{enumerate}
 \item Second level item
 \item Second level item
 \begin{enumerate}
 \item Third level item
 \item Third level item
 \begin{enumerate}
 \item Fourth level item
 \item Fourth level item
 \end{enumerate}
 \end{enumerate}
 \end{enumerate}
 \end{enumerate}
 
 \begin{enumerate}
 \item First level item
 \item First level item
 \begin{enumerate}
 \setcounter{enumii}{4}
 \item Second level item
 \item Second level item
 \begin{enumerate}
 \item Third level item
 \item Third level item
 \begin{enumerate}
 \item Fourth level item
 \item Fourth level item
 \end{enumerate}
 \end{enumerate}
 \end{enumerate}
 \end{enumerate}
 
 \subsection{Unordered lists}
 
 \begin{itemize}
 \item  First Level
 \begin{itemize}
 \item  Second Level
 \begin{itemize}
 \item  Third Level
 \begin{itemize}
 \item  Fourth Level
 \end{itemize}
 \end{itemize}
 \end{itemize}
 \end{itemize}

 \renewcommand{\labelitemi}{$\blacksquare$}
 \renewcommand\labelitemii{$\square$}
 \begin{itemize}
 \item  First Level
 \begin{itemize}
 \item  Second Level
 \begin{itemize}
 \item  Third Level
 \begin{itemize}
 \item  Fourth Level
 \end{itemize}
 \end{itemize}
 \end{itemize}
 \end{itemize}

\begin{itemize}
 \item  Default item label for entry one
 \item  Default item label for entry two
 \item[$\square$]  Custom item label for entry three
\end{itemize}

\end{document}