latex notes

Bon, je try to write a report with latex and got some errors during the compilation. I start to solve them one by one. Here are some notes.

The basic structure of the text is as follows.

\documentclass[12pt,a4paper]{report} #specify font size, paper size, doc type
\title{report title }
\author{me}
\usepackage{amsmath} #include the latex packages.
\usepackage{graphicx}
\usepackage{hyperref}
\usepackage{url}

\begin{document} # the beginning of the main document
\maketitle
\chapter{Introduction}
\section{}
\subsection{}
\end{document} # end of document

1) to use \url for presenting a web link, I need include \usepackage{url} in the beginning. It is very convenient to just write \url {www.link.com} in the text.

2) For representing degrees, use $^{\circ}$

3) insert a figure:
\begin{figure}
\begin{center}
\includegraphics[width=7cm,height=50mm]{figure.jpg}
\caption{Figure caption.}
\end{center}
\end{figure}

4) insert items
\begin{itemize}
\item{text}
\end{itemize}