\documentclass[twoside]{book} % You'll need to use this...
\usepackage{pagevisuals}% Overleaf's template
\usepackage{fancyhdr} % To add some headers/footers
\usepackage{lipsum} % For generating some sample text
% Use the \showhelp command to typeset some brief documentation
\setmarginpars{5}{35} % set \marginparsep, \marginparwidth
\setheadfoot{10}{5}{12} %set \headheight, \headsep, \footskip
\setpage{250}{370}{195}{265}{15}{18}{10}{10} %see documentation: use the command \showhelp
%-------------------------------------------------------
\begin{document}
\showvisuals %turn on display of rulers/borders
%------------ An example of using fancyhdr.sty ---------
\fancyhead[LE]{{\fontsize{12}{12}\selectfont\thepage}}
\fancyhead[RE]{\textsc{text for left-hand pages}}
\fancyhead[LO]{\textsc{Text for right-hand pages}}
\fancyhead[RO]{{\fontsize{12}{12}\selectfont\thepage}}
\pagestyle{fancy}
%-------------------------------------------------------
\showhelp %typesets some brief documentation
\showvalues %typesets the content of mypagesetup.tex
%
\lipsum[1-10]%<--from lipsum.sty to generate some sample text
\end{document}
