How to change a page layout in a Overleaf template?

Question

I am using a template from Overleaf enter link description here

However, I have no idea where to change the page layout. I want to write more in my Abstract page, while other page maintained the same as the template.

If I used this:

\usepackage[top=2cm,left=1.2cm,right=1.2cm, bottom=1cm]{geometry}

It will change all the pages. I just want Abstract page.

In the photo below, I want to word Abstract move to top a little, so that I can write more. However, others title remain the same as template, Am I able to do that?

For example:

\include{structure/abstract}  %-> page size larger
\include{structure/acknowledgements}  %--> page remain in original size

  \documentclass[12pt,oneside]{book}  % Remove draft option to show figures (for final draft), otherwise keep for faster production
\usepackage{uorthesis}  % Loads the LaTeX style package
\usepackage[backend=biber, style=authoryear, dashed=false]{biblatex}
\addbibresource{references.bib}
\usepackage{titlesec}
% \titleformat{\chapter}[block]
%   {\normalfont\sffamily\LARGE\bfseries\filcenter}
%   {\filcenter\chaptertitlename\ \thechapter\filcenter\}{20pt}{\huge}
\titleformat{\chapter}[block]   {\normalfont\sffamily\LARGE\bfseries\filcenter}   {\filcenter\chaptertitlename\ \thechapter\filcenter\}{20pt}{\huge}[{\titlerule[1pt]}]
% Put custom packages to be loaded here
% \usepackage{linguex}  % For linguistic examples
% \usepackage{tikz}     % For drawing
\begin{document}
% Title page
% All subsequent pages must be numbered, title page is considered page i,
% front matter is numbered in lowercase Roman numerals
\pagestyle{fancy}
\pagenumbering{roman}
\setcounter{page}{2}
\doublespacing
%%%%%%%%%%%%%%%%%%%% DISSERTATION CONTENT %%%%%%%%%%%%%%%%%%%%
% Regular numbering starts now, first page of first chapter is page 1
\clearpage
\setcounter{page}{0}
\pagenumbering{arabic}
% Body
\include{structure/abstract}
\include{structure/acknowledgements}
% References
\clearpage
\addcontentsline{toc}{chapter}{Bibliography}
\markboth{\MakeUppercase{Bibliography}}{}
\singlespacing
\printbibliography
\end{document}

uorthesis.sty file:

% This defines everything necessary for a thesis
% Master's/PhD at UoR (or anywhere else).
%
% Do what you will with this package
% 
\NeedsTeXFormat{LaTeX2e}[1994/06/01]
\ProvidesPackage{uorthesis}
  [2018/01/18 v0.01 LaTeX package for UOR thesis]
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{microtype}
\usepackage[english]{babel}
\usepackage{graphicx}
\usepackage{enumitem}
\setlist{nosep} % Removes too much vertical spacing in lists
\usepackage{booktabs}           % makes tables look good
\usepackage{fancyhdr}           % For page number in the upper right (required) and other running headers(optional)
\usepackage{setspace}           % For double-spacing (required)
\usepackage{titlesec}           % For keeping chapter/chapter titles single-spaced
\usepackage{etoolbox}           % For the flag determining if front matter goes into the TOC
\usepackage{float}              % Helps float images to the top
\RequirePackage{xcolor}
% Define custom colors
\definecolor{darkblue}{rgb}{0, 0, 0.5}
\usepackage[colorlinks=true, allcolors=darkblue]{hyperref}           % Adds hyperlinks in the pdf
\usepackage{csquotes}           % Makes quotes look good
\usepackage[font=small,labelfont={bf,sf}, textfont={sf}, justification=centering]{caption}
%% Font setup
\usepackage{mathptmx}
% \usepackage{lmodern}
\usepackage{helvet}
% Header height (to avoid fancyhdr error)
\setlength{\headheight}{13.6pt}
% Header formatting for regular pages
\fancyhf{}
\fancyhead[L]{\it\small\leftmark}
\fancyhead[R]{\small\thepage}
% Header formatting for chapter title pages
\fancypagestyle{plain}{%
  \fancyhf{}
  \fancyhead[R]{\small\thepage}
  \renewcommand{\headrulewidth}{0pt}
}
% Formatting of chapter and chapter titles: keep them single-spaced in the midst of double-spaced text
\usepackage{sectsty}
\titleformat{\chapter}[hang]{\Huge\sffamily\bfseries}{\thechapter{. }}{0pt}{\Huge}
\allsectionsfont{\normalfont\sffamily\bfseries}
\usepackage{subfigure}
\usepackage[subfigure]{tocloft} % subfigure option only if using subfigure package
\renewcommand{\cfttoctitlefont}{\Huge \bfseries \sffamily} % ToC title
\addto\captionsenglish{
\renewcommand{\listfigurename}{\textsf{List of Figures}}
\renewcommand{\listtablename}{\textsf{List of Tables}}
}
% Flag for whether to add front matter to TOC
\newtoggle{fulltoc}
\toggletrue{fulltoc}  % Change to \togglefalse{fulltoc} to remove front matter
\renewcommand{\contentsname}{Table of Contents}
\endinput
%%
%% End of file `uorthesis.sty'.