\documentclass{standalone}
\usepackage{tikz}
\usepackage[hypertex]{hyperref}
\usetikzlibrary{shapes.geometric, arrows.meta, positioning}

\begin{document}
\tikzset{
  process/.style={rectangle, minimum width=5cm, minimum height=1cm, text centered, draw=black},
  arrow/.style={thick,->,>=stealth},
}
\begin{tikzpicture}
\node (penelope) [process] {\href{\#penelope}{Penelope}};
\node (cassavetes) [process, right=of penelope] {\href{\#cassavetes}{Cassavetes}};
\node (beatrix) [process, below=of penelope] {\href{\#beatrix}{BEATRIX}};
\node (tinynet) [process, below=of beatrix] {\href{\#tinynet}{TinyNeT}};
\node (tnt-router) [process, right=of tinynet] {\href{\#tinynet-router}{TinyNeT-Router}};
\draw [arrow] (penelope) -- (cassavetes);
\draw [arrow] (tinynet) -- (tnt-router);
\end{tikzpicture}
\end{document}