\documentclass[12pt]{article}
\usepackage{graphicx,amssymb,hyperref}
\usepackage[a4paper,top=2cm,bottom=2cm,left=2cm,right=2cm]{geometry}
\begin{document}

%%%%%%%%%% Title
\begin{center}
\section*{Title of your abstract}
\end{center}

%%%%%%%%%% Authors
\begin{center}
\large{N. Surname$^{\dagger,1}$, N. Surname$^{1,2}$, N. Surname$^{2,3}$, ...}
\end{center}

%%%%%%%%%% Affiliations
{\footnotesize
\begin{enumerate}\centering
\item[$\dagger$] {\tt user@domain} (speaker)
\item Institution
\item Institution
\item ... ... ...
\end{enumerate}}

%%%%%%%%%% Abstract
Write here your abstract. Please do not exceed one page, including references.

%%%%%%%%%% References
\noindent
{\footnotesize
\begin{thebibliography}{99}

\bibitem{reference1} Authors
\newblock {\em Title }, 
\newblock {Journal/book information}

\bibitem{reference2} Authors
\newblock {\em Title }, 
\newblock {Journal/book information}

\end{thebibliography}
}

\end{document} 