\documentclass[]{beamer}

\usetheme{Madrid}

\usenavigationsymbolstemplate{}

\title{Main Title}

\author{Jane Doe}

\institute{University A}

\date{\today}

\begin{document}

\begin{frame}

\titlepage % Print the title page as the first slide

\end{frame}

\begin{frame}

\frametitle{First Page}

\begin{exampleblock}{Example}

This is an example which will be used later.

\end{exampleblock}

\end{frame}

\begin{frame}

\frametitle{Second Page}

\label{important}

\begin{itemize}

\item Item 1

\item Item 2

\end{itemize}

\end{frame}

\begin{frame}

\frametitle{Third Page}

\begin{itemize}

\item In this slide, we are going to use the sample example on slide~\ref{important}.

\end{itemize}

\end{frame}

\end{document}