main.tex

\documentclass[openright,twoside,a4paper,english,12pt]{book}

\input{packages}
\input{commands}
\input{glossary}

% Set includeonly if you only want to compile one chapter
% See https://en.wikibooks.org/wiki/TeX/includeonly
% Just modify it to choose which chapter(s) to compile
% This is useful when you are only working on one chapter
%  so you only have to wait for *one* chapter to compile each time.
%
% \includeonly{chap1/chap1}
%

\begin{document}

    \frontmatter    % page numbering i, ii, ...
    \include{titlepage}
    
    \spacing{1.5}
    % "1.5 line spacing" is ambiguous - see https://tex.stackexchange.com/q/65849
    % but the above should be what is intended in the regulations
    
    %% Preface contains:
    %%  Abstract, Lay summary, Declaration, Acknowledgements
    %%  table of contents, list of figures, tables, glossary
    \include{preface}

    % Turn on line numbering
    % Just remove this line to turn it off
    \linenumbers
    
    \mainmatter     % page numbering 1, 2, ...
    % 
    \include{chap1/chap1}
    \include{chap2/chap2}
    
    \cleardoublepage
    % Place the bibliography, with single-spacing and small font
    % "heading=bibintoc" makes it appear in the table of contents
    % \renewcommand{\baselinestretch}{1.0}
    \renewcommand*{\bibfont}{\small}
    \begin{spacing}{1}  % temporarily change to more compact lines
        \printbibliography[heading=bibintoc]
    \end{spacing}
    
    \include{appendices/appendix1}

\end{document}