\documentclass{fithesis3}
\thesissetup{autoLayout = false}
\thesisload
\setcounter{tocdepth}{4}
\setcounter{secnumdepth}{0}
\begin{document}
  \tableofcontents

  \part{abc}
  \chapter{def}
  \section{ghi}
  \subsection{jkl}
  \subsubsection{mno}
  \paragraph{pqr}
  \subparagraph{stu}
  \chapter{vwx}
  \section{yz}

  \part{abc}
  \chapter{def}
  \section{ghi}
  \subsection{jkl}
  \subsubsection{mno}
  \paragraph{pqr}
  \subparagraph{stu}
  \chapter{vwx}
  \section{yz}
\end{document}