Some templates may be available in Overleaf. For others check the author resources on the journal or publisher's homepage.
The new version of the template uses BibLateX and biber instead of bibtex. For now, both versions are running but the new template has a range of bibliographic options for various requirements.
In this, all the person needs to do is uncomment their choice of bibliography style. The class file does the rest.
% Generate the references list
% This *requires* biblatex and biber to be installed.
% Comment out the \APAReferences line and uncomment the preferred format.
\APAReferences{}
%\IEEEReferences{}
%\IEEEAlphaReferences{}
%\ChicagoNotesReferences{}
%\ChicagoAuthorDateReferences{}
%\HarvardAuthorDateReferences{}
%\VancouverReferences{}
% The bib resource is the file name for the bibliography file. Change it to suit your needs.
\addbibresource{bibFile.bib}
References can be copied to a BibTex format from EndNote.
Paste into Notepad and save. (In LaTeX or the text editor you are using you can change the .txt to .bib.)