\documentclass{article}
\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\title{Übung zur Projektstruktur}

\begin{document}
\maketitle
\tableofcontents

\include{section1}
\include{section2}
\include{section3}

\end{document}