%% Dokumentdeklaration
\documentclass[12pt,a4paper]{report}

%% Präambel
\usepackage{lipsum}
\usepackage[ngerman]{babel}
\usepackage{abstract}
\usepackage{subfiles}

\usepackage[onehalfspacing]{setspace}


\title{\LaTeX Demo}
\author{}
\date{\ }

%% Dokumentbegin
\begin{document}
\

\subfile{subfile1}
\subfile{subfile2}

\end{document}