\documentclass[12pt,twoside]{report}
\usepackage[a4paper,top=25mm,bottom=25mm,inner=35mm,outer=25mm]{geometry}
\include{preamble}
\newcommand{\thetitle}{Thesis Title}
\newcommand{\theauthor}{Author Name}
\newcommand{\degree}{Integrated Dual Degree (B.Tech.+ M.Tech.)}
\newcommand{\program}{Industrial Chemistry}
\newcommand{\department}{Department of Chemistry}
\newcommand{\institute}{Indian Institute of Technology (Banaras Hindu University), Varanasi}
\newcommand{\institutecity}{Varanasi, India}
\newcommand{\institutewithaddress}{Indian Institute Of Technology \\ (Banaras Hindu University) \\ Varanasi – 221 005}
\newcommand{\supervisor}{Prof. Abc Xyz}
\newcommand{\supervisoraffiliation}{\department{} \\ \institutewithaddress{}}
\newcommand{\cosupervisor}{}
\newcommand{\cosupervisoraffiliation}{}
\newcommand{\extsupervisor}{}
\newcommand{\extsupervisoraffiliation}{}
\newcommand{\projectstart}{January 2020}
\newcommand{\projectend}{May 2021}
\newcommand{\rollno}{12345678}
\begin{document}
\pagenumbering{roman}
\include{preliminaries}
\pagenumbering{arabic}
\include{chapters}
\include{references-and-bibliography}
\end{document}
