Some example LaTeX

\documentclass{scrbook} %---------------------------------------------------v-1-

\usepackage{fontspec}
\usepackage{scrlayer-scrpage}
\usepackage{microtype}

\usepackage[ papersize={6in, 9in} ]{geometry}

\title{The Title of This Book}
\subtitle{The Subtitle}
\author{Some Person}
\date{} % I seem to recall that the \maketitle command needs an empty
        % \date{} command here, or it does some default thing.

% Don’t remember
\usepackage[perpage,symbol*]{footmisc}
% Literally for poetry. I’m guessing you don’t need this.
\usepackage{verse}

% Special consideration for how ellipses (“...”) work.
\usepackage{ellipsis}
\renewcommand{\ellipsisgap}{0.075em}

\newcommand\ChapterWithSubtitle[2]{
  \chapter[#1: {\itshape#2}]{#1\\[2ex]\Large\itshape#2}
}

% This is that thing that makes the First letter of a chapter real big.
% I doubt it's something you want, but look it up online for usage.
\usepackage{lettrine}

% Makes the em-dash character play a bit nicer with line breaks and whitespace.
\def\dash---{\kern.16667em---\penalty\exhyphenpenalty\hskip.16667em\relax}

\begin{document} %----------------------------------------------------------v-1-

\maketitle % Uses the metadata provided in the block above that starts with
           % “\title{…”

\tableofcontents % Uses metadata generated by chapter headings below, which is
                 % part of why you have to compile multiple times in LaTeX.

% Files that implicitly end in .tex. The \input command literally inserts them
% character by character, which means compilation can’t cache per-file output.
% Might be good enough, since \input makes other considerations much simpler
% than the alternative I don’t recall the name of, lol.
\input{"chapters/name_of_file_1"}
\input{"chapters/name_of_file_2"}
\input{"chapters/name_of_file_3"}
\input{"chapters/name_of_file_4"}
\input{"chapters/name_of_file_5"}

% …The idea being that you don’t have to follow the syntax of a complete,
% independent .tex file. It also lets you do crazy, perhaps useful stuff like
% this:

\chapter{Name of This Chapter}

\input{"chapters/name_of_this_chapter"}

\end{document} %------------------------------------------------------------^-1-

% Below: a Vim modeline that defines a special character sequence that allows
% you to tell Vim where you want your code to fold. See “:help fold-marker”. It
% also enforces some whitespace concerns.

% I’m pretty sure modelines are frowned upon nowadays, and insecure, but if you
% change your 'foldmarker' setting per-file (which is also frowned on, probably
% because it necessitates use of a modeline. lol), it’s literally the only way
% to make it work. I just hate the default "fmr={{{,}}}".

% vim: set fmr=-v-,-^- fdm=marker et ts=2 sw=0 sts=-1 :