pdflatex document.tex
# Run twice if you have references/citations
pdflatex document.tex

\documentclass{article}

% Preamble: packages and settings go here
\usepackage[utf8]{inputenc}
\usepackage{amsmath}

\title{My First Document}
\author{Jane Doe}
\date{\today}

\begin{document}

\maketitle

Hello, world! This is my first \LaTeX{} document.

\end{document}

\textbf{Bold text}
\textit{Italic text}
\underline{Underlined text}
\emph{Emphasized text}
\texttt{Monospace text}
\textsc{Small Caps}

{\tiny tiny text}
{\small small text}
{\normalsize normal text}
{\large large text}
{\Large Larger text}
{\huge huge text}

\begin{itemize}
  \item First point
  \item Second point
\end{itemize}

\begin{enumerate}
  \item Step one
  \item Step two
\end{enumerate}

\begin{description}
  \item[LaTeX] A typesetting system
  \item[TeX] The engine underneath
\end{description}

Inline: $E = mc^2$

Display:
\[
  E = mc^2
\]

Or using amsmath:
\begin{equation}
  E = mc^2
\end{equation}

\begin{pmatrix}
  a & b \\
  c & d
\end{pmatrix}

\begin{align}
  a &= b + c \\
  x &= y - z
\end{align}

\usepackage{graphicx}

\begin{figure}[h]
  \centering
  \includegraphics[width=0.6\textwidth]{image.png}
  \caption{A descriptive caption}
  \label{fig:example}
\end{figure}

\begin{table}[h]
  \centering
  \begin{tabular}{|l|c|r|}
    \hline
    Name & Age & City \\
    \hline
    Alice & 30 & NYC \\
    Bob & 25 & LA \\
    \hline
  \end{tabular}
  \caption{Sample data table}
\end{table}

\section{Introduction}
\label{sec:intro}

As discussed in Section~\ref{sec:intro}...

See Figure~\ref{fig:example} on page~\pageref{fig:example}.

@article{einstein1905,
  author  = {Einstein, Albert},
  title   = {Zur Elektrodynamik bewegter K{\"o}rper},
  journal = {Annalen der Physik},
  year    = {1905}
}

\usepackage{cite}
...
As shown by \cite{einstein1905}...

\bibliographystyle{plain}
\bibliography{references}

% Simple command
\newcommand{\R}{\mathbb{R}}

% Command with arguments
\newcommand{\vect}[1]{\mathbf{#1}}

% Usage
The set \R represents real numbers.
The vector \vect{v} has magnitude...

\documentclass{beamer}
\usetheme{Madrid}

\title{My Presentation}
\author{Jane Doe}

\begin{document}

\frame{\titlepage}

\begin{frame}{Introduction}
  This is my first slide.
\end{frame}

\end{document}

\usepackage{tikz}

\begin{tikzpicture}
  \draw[thick,->] (0,0) -- (2,0) node[right]{$x$};
  \draw[thick,->] (0,0) -- (0,2) node[above]{$y$};
  \draw[blue,thick] (0,0) circle (1);
\end{tikzpicture}

\documentclass{book}
\begin{document}

\include{chapters/chapter1}
\include{chapters/chapter2}

\end{document}