LaTeX Forum

\listfiles
\documentclass{scrartcl}

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

\usepackage{enumitem}

\begin{document}

\begin{enumerate}
	\item Eins
	\item Zwei
\end{enumerate}
%
\begin{enumerate}
	\item[3a.] Drei a
	\item[3b.] Drei b
\end{enumerate}
%
\begin{enumerate}[start=4]
	\item Vier
	\item Fünf
\end{enumerate}

\end{document}

\documentclass{scrartcl}

\usepackage{enumitem}
\setlist[enumerate]{label=\arabic*.,align=left,leftmargin=!,
  labelindent=0pt,labelwidth=1.5em,labelsep=.5em}
\setlist[enumerate,2]{before=\stepcounter{enumi},label=\arabic{enumi}\alph*.,
  labelindent=-2em}

\begin{document}
\noindent Text
\begin{enumerate}
  \item Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy
    eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam
    voluptua.
  \item Test
  \begin{enumerate}
    \item Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy
      eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam
      voluptua.
    \item Test
  \end{enumerate}
  \item Test
  \begin{enumerate}
    \item Test
    \item Test
    \item Test
  \end{enumerate}
  \item Test
\end{enumerate}
Text
\end{document}