LaTeX.org

I'm new in this forum and now I have found out that can illustrate my problem.

So once more: The complete code is

\documentclass{report}

\usepackage[english]{babel}
\usepackage{enumerate}

\begin{document}
\begin{enumerate}[{\bf Problem} 1\quad]
\item bla bla
\begin{enumerate}
\item
\item ...

Can somebody explain this code

\begin{enumerate}[{\bf Problem} 1\quad]
\item bla bla
\begin{enumerate}
\item
\item
\end{enumerate}
\item
\begin{minipage}[t]{1.0\linewidth}
bla bla bla
\begin{enumerate}
\item
\item
\end{enumerate}
\end{minipage}
\item
\parbox[t]{1.0\linewidth ...