LaTeX basics for beginners

\documentclass{article}

% Preamble - document settings and packages
\title{My Document}
\author{Your Name}
\date{\today}

\begin{document}

\maketitle

% Your content goes here

\end{document}

\documentclass{article}    % For short documents and articles
\documentclass{report}     % For longer reports with chapters
\documentclass{book}       % For books
\documentclass{letter}     % For letters
\documentclass{beamer}     % For presentations

\documentclass[12pt, a4paper]{article}  % 12pt font on A4 paper
\documentclass[twocolumn]{article}      % Two-column layout

\section{Introduction}
This is the introduction.

\subsection{Background}
Some background information.

\subsubsection{Historical context}
More detailed context.

\paragraph{Note}
A named paragraph.

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

{\tiny Tiny text}
{\small Small text}
{\normalsize Normal text}
{\large Large text}
{\Large Larger text}
{\LARGE Even larger text}
{\huge Huge text}
{\Huge Hugest text}

First paragraph.

Second paragraph. Use blank lines to separate paragraphs.

Force a line break here.\\
New line without a paragraph break.

\begin{itemize}
  \item First item
  \item Second item
  \item Third item
    \begin{itemize}
      \item Nested item
      \item Another nested item
    \end{itemize}
\end{itemize}

\begin{enumerate}
  \item First item
  \item Second item
  \item Third item
\end{enumerate}

\begin{description}
  \item[Term 1] Definition of term 1
  \item[Term 2] Definition of term 2
\end{description}

The equation $E = mc^2$ is famous.
The variable $x$ represents the unknown.

\[
  f(x) = x^2 + 2x + 1
\]

\begin{equation}
  \int_{0}^{\infty} e^{-x^2} dx = \frac{\sqrt{\pi}}{2}
\end{equation}

% Greek letters
\alpha, \beta, \gamma, \Delta, \pi, \Sigma

% Operators
\times, \div, \pm, \leq, \geq, \neq, \approx

% Fractions and roots
\frac{numerator}{denominator}
\sqrt{x}
\sqrt[3]{x}  % cube root

% Subscripts and superscripts
x^2, x_i, x^{2n}, x_{i,j}

% Summations and integrals
\sum_{i=1}^{n} x_i
\int_{a}^{b} f(x) dx
\prod_{i=1}^{n} x_i

\[
  \begin{matrix}
    a & b \\
    c & d
  \end{matrix}
\]

% With brackets
\[
  \begin{bmatrix}
    1 & 2 & 3 \\
    4 & 5 & 6 \\
    7 & 8 & 9
  \end{bmatrix}
\]

\begin{table}[h]
  \centering
  \begin{tabular}{|l|c|r|}
    \hline
    Left & Center & Right \\
    \hline
    1 & 2 & 3 \\
    4 & 5 & 6 \\
    \hline
  \end{tabular}
  \caption{A sample table}
  \label{tab:sample}
\end{table}

\begin{figure}[h]
  \centering
  \includegraphics[width=0.5\textwidth]{image.png}
  \caption{A sample figure}
  \label{fig:sample}
\end{figure}

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

\begin{equation}
  E = mc^2
  \label{eq:einstein}
\end{equation}

As shown in Section~\ref{sec:intro}, Equation~\ref{eq:einstein} is important.

\documentclass{article}

% Common packages
\usepackage{amsmath}     % Enhanced math features
\usepackage{graphicx}    % Include images
\usepackage{hyperref}    % Clickable links
\usepackage{geometry}    % Page layout
\usepackage{booktabs}    % Professional tables

\begin{document}
% Your content
\end{document}

% This is a comment
This text will appear. % This comment won't

% Comments are useful for:
% - Explaining complex code
% - Temporarily disabling content
% - Leaving notes for collaborators

% These need backslash to print literally:
\$ \% \& \_ \{ \} \# \\

% Quotes
`single quotes'
``double quotes''

% Dashes
- hyphen
-- en-dash
--- em-dash

\begin{document}

According to Smith~\cite{smith2020}, this is true.

\bibliographystyle{plain}
\bibliography{references}

\end{document}