How to set margin & font size while converting tex to pdf?

Question

I'm trying to make a PDF book out of a Github tutorial at https://github.com/redguardtoo/mastering-emacs-in-one-year-guide/blob/master/guide-en.org (to read it comfortably on my iPad) To do that, I exported the Emacs org file into a tex file and converted it into a pdf by:

$ pandoc -s emacs-in-one-year.tex -o emacs-in-one-year.pdf

and it got converted but the resulting PDF looked out of proportions; the fonts were quite small and there were huge margins on four sides of the texts. For a screenshot see: https://i.hizliresim.com/kXdlp9.png

I've searched Stackoverflow for this problem and applied the suggested solutions but none of them ever worked, the margins are still huge and fonts are small. The modified tex file looks like below now. How can I make fonts larger and margins smaller? Thanks.

% Created 2017-12-04 Mon 18:08
\documentclass[13pt, a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fixltx2e}
\usepackage{graphicx}
\usepackage{longtable}
\usepackage{float}
\usepackage{wrapfig}
\usepackage{rotating}
\usepackage[normalem]{ulem}
\usepackage{amsmath}
\usepackage{textcomp}
\usepackage{marvosym}
\usepackage{wasysym}
\usepackage{amssymb}
\usepackage{hyperref}
\usepackage{fullpage}
\setlrmarginsandblock{1cm}{1cm}{*} % Left and right margin
\setulmarginsandblock{2cm}{2cm}{*}  % Upper and lower margin
\checkandfixthelayout
\usepackage{geometry}
\geometry{
  paper=a4paper,
  margin=10pt,
 includeheadfoot
}
\tolerance=1000
\setcounter{secnumdepth}{0}
\author{REPL & The Code Maker}
\date{\today}
\title{Emacs in one year}
\hypersetup{
  pdfkeywords={},
  pdfsubject={},
  pdfcreator={Emacs 25.2.1 (Org mode 8.2.10)}}
\begin{document}

\maketitle
\section*{Master Emacs in one year \hfill{}\textsc{emacs:en}}
\label{sec-1}
Author: Chen Bin (redguardtoo)

Version: 20150424

Updated: \textit{<2015-04-24 Fri>}

Created: \textit{[2012-01-31 Tue 15:08]}

Copyright: This work is licensed under the         
 \href{http://creativecommons.org/licenses/by-nc-nd/3.0/}{Creative Commons     Attribution-NonCommercial-NoDerivs 3.0 Unported License}.

\subsection*{Introduction}
\label{sec-1-1}
I was a Microsoft fan because I was born in China. There was no Unix     culture when I was young.

When I convert

Answer 1

I have edited your example to run without error and have I think the margins that you intended (but these margins are much too small).

% Created 2017-12-04 Mon 18:08
\documentclass[
% there is no 13pt option so 13pt wouldgive 10pt 
12pt,
a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
% do not use\usepackage{fixltx2e}
\usepackage{graphicx}
\usepackage{longtable}
\usepackage{float}
\usepackage{wrapfig}
\usepackage{rotating}
\usepackage[normalem]{ulem}
\usepackage{amsmath}
\usepackage{textcomp}
\usepackage{marvosym}
\usepackage{wasysym}
\usepackage{amssymb}
\usepackage{hyperref}
% use geometry instead \usepackage{fullpage}

% memoir only \setlrmarginsandblock{1cm}{1cm}{*} % Left and right margin
% memoir only \setulmarginsandblock{2cm}{2cm}{*}  % Upper and lower margin
% memoir only  \checkandfixthelayout
\usepackage{geometry}
\geometry{
  paper=a4paper,
  margin=10pt, % are you sure you want margins that small?????
               % that will not print on may home printers and will make a text block
               % too wide to read with comfort
 includeheadfoot
}
\tolerance=1000
\setcounter{secnumdepth}{0}
%\author{REPL & The Code Maker}
% \and not &
\author{REPL \and The Code Maker}

\date{\today}
\title{Emacs in one year}
\hypersetup{
  pdfkeywords={},
  pdfsubject={},
  pdfcreator={Emacs 25.2.1 (Org mode 8.2.10)}}
\begin{document}

\maketitle
\section*{Master Emacs in one year \hfill{}\textsc{emacs:en}}
\label{sec-1}
Author: Chen Bin (redguardtoo)

Version: 20150424

Updated: \textit{<2015-04-24 Fri>}

Created: \textit{[2012-01-31 Tue 15:08]}

Copyright: This work is licensed under the         
 \href{http://creativecommons.org/licenses/by-nc-nd/3.0/}
      {Creative Commons     Attribution-NonCommercial-NoDerivs 3.0 Unported License}.

\subsection*{Introduction}
\label{sec-1-1}
I was a Microsoft fan because I was born in China. There was no Unix culture when I was young.

\end{document}