diff --git a/CELbeamer.cls b/CELbeamer.cls
index bfadfb1..3e20a6e 100644
--- a/CELbeamer.cls
+++ b/CELbeamer.cls
@@ -22,6 +22,8 @@
 \newif\ifkitgrid
 \newif\ifspaceforface
 \spaceforfacefalse
+\newif\ifoverviewatsection
+\overviewatsectionfalse
 
 \def\groupname#1{\def\@groupname{#1}}
 \def\groupnamewidth#1{\def\@groupnamewidth{#1}}
@@ -55,6 +57,9 @@
 \DeclareOption{spaceforface}{
   \spaceforfacetrue
 }
+\DeclareOption{overviewatsection}{
+  \overviewatsectiontrue
+}
 
 \ExecuteOptions{en,bigfoot,helvet}
 
@@ -131,7 +136,7 @@
 %% ┗━━━━━━━━━━━━━━┛
 
 %% ┏━━━━━━━━━━━━━━━┓
-%% ┃ Folien-Layout ┃
+%% ┃ Frame-Layout ┃
 %% ┗━━━━━━━━━━━━━━━┛
 
 % Seitenverhältnis
@@ -608,7 +613,9 @@
   \setbeamertemplate{background}{\hskip#1\includegraphics[height=\paperheight]{\@titleimage}}
 }
  
-% Table of contents
+% ┏━━━━━━━━━━━━━━━━━━━┓
+% ┃ Table of contents ┃
+% ┗━━━━━━━━━━━━━━━━━━━┛
 
 \define@key{beamerframe}{tableofcontents}[blue]{%
   \setbeamertemplate{background}{
@@ -636,6 +643,10 @@
     \end{textblock*}
 }
 
+% ┏━━━━━━━━━━━━━━━━━━━┓
+% ┃ /Table of contents ┃
+% ┗━━━━━━━━━━━━━━━━━━━┛
+
 % siehe README.md
 \define@key{beamerframe}{picture}{%
   \titleimage{#1}
@@ -650,7 +661,7 @@
 % └──────────────────┘
 
 %% ┏━━━━━━━━━━━━━━━━┓
-%% ┃ /Frame-Layout ┃
+%% ┃ /Frame-Layout  ┃
 %% ┗━━━━━━━━━━━━━━━━┛
 
 %% ┏━━━━━━━━━━━━┓
@@ -797,13 +808,16 @@
 \defbeamertemplate{background}{KIT 2025 title vertical}{
     \begin{beamercolorbox}[ht=\paperheight,wd=\kitcolumnthreeright]{title text box}
     \end{beamercolorbox}%
-    \begin{beamercolorbox}[ht=\paperheight,wd=\dimexpr2\kitcolumn+3\kitcolumnsep\relax]{title logo box}%
-    \ifdefined\@titleimage%
-      \ifx\@titleimage\empty\else%
-      \includegraphics[height=\paperheight]{\@titleimage}%
+    % \ifspaceforface{}
+    % \else
+      \begin{beamercolorbox}[ht=\paperheight,wd=\dimexpr2\kitcolumn+3\kitcolumnsep\relax]{title logo box}%
+      \ifdefined\@titleimage%
+        \ifx\@titleimage\empty\else%
+        \includegraphics[height=\paperheight]{\@titleimage}%
+        \fi%
       \fi%
-    \fi%
     \end{beamercolorbox}%
+    % \fi
     \begin{beamercolorbox}[ht=\paperheight,wd=\dimexpr\kitcolumn+\kitoutermargin\relax,center,rightskip=\kitoutermargin]{title logo box}
       \ifdefined\@fundinglogos%
         \ifx\@fundinglogos\empty\else%
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3635964..2d6c491 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,4 +12,5 @@ All changes of this template is documented in this file.
 - Added the option for adding fundinglogos onto the title page
 - Added the group logo onto overview page
 - Changed the normal fontsize to 19pt
-- Added the spaceforface mode to leave space on the right for recording
\ No newline at end of file
+- Added the spaceforface mode to leave space on the right for recording
+- Added a newif for overview at section option !!! Modification is still needed
\ No newline at end of file
diff --git a/presentation.tex b/presentation.tex
index 5640ffc..1d18567 100644
--- a/presentation.tex
+++ b/presentation.tex
@@ -4,10 +4,10 @@
 %% Modified by: Hedongliang Liu
 %% Last modified on: 14.08.2025
 %%%%%%%%%%% CEL beamer class %%%%%%%%%%%%%%%
-\documentclass[spaceforface, kitgrid]{CELbeamer} 
+\documentclass[overviewatsection]{CELbeamer} 
 %% default options: en, helvet, bigfoot (12pt)
 %% other options: de, franklin, smallfoot (11pt), navbaron, kitgrid, handout, 
-%% spaceforface 
+%% spaceforface, overviewatsection
 
 %%%%%%%%%%% Load packages (from previous CEL template %%%%%%%%%%%%%%%
 \newcommand{\templates}{packages}
@@ -15,7 +15,15 @@
 \input{\templates/booleans.tex}
 % \input{\templates/modifications.tex}
 % \input{\templates/makros_own.tex}
+\overviewatsectiontrue% toggles to show the toc
 
+\AtBeginSection{%
+\ifoverviewatsection
+\begin{frame}[tableofcontents=blue]{Overview}
+    \tableofcontents[currentsection, subsectionstyle=show/show/hide]
+\end{frame}
+\fi
+}
 
 %%%%%%%%%%% Group info: logo must be in the directory logos/ %%%%%%%%%%%%%%%
 %% If no group logo is desired, please call \grouplogo{} 
@@ -59,7 +67,20 @@
 	\tableofcontents
 \end{frame}
 
-\section{Basic options}
+\section{Basic Usage}
+\begin{frame}{Usages Options}
+	The following options can be used by putting the \texttt{<option>} in the \texttt{\textbackslash documentclass[<option>]\{CELbeamer.cls\}} command:
+\begin{itemize}
+	\item \texttt{en} \textit{(default)} for English, \texttt{de} for German
+	\item \texttt{helvet} \textit{(default)} for Helvetica font, \texttt{franklin} for Franklin Gothic font
+	\item \texttt{bigfoot} \textit{(default)} for 12pt font size, \texttt{smallfoot} for 11pt font size
+	\item \texttt{navbaron} to show the navigation bar
+	\item \texttt{kitgrid} to show the grid of rows and columns
+	\item \texttt{handout} to create a handout version of the slides
+	\item \texttt{spaceforface} to leave space for face in recording 
+	\item \texttt{overviewatsection} to show the table of contents at each section
+\end{itemize}
+\end{frame}
 \begin{frame}{Font Size Examples}
 	\tiny Tiny text
 
@@ -230,28 +251,6 @@
 	% For more colors, see \ref{frame:kit-colors}.
 \end{frame}
 
-% \subsection{Spezial Frames}
-% \begin{frame}[picture 66 vertical,picture=images/palladio_bauplan,kitlogo=black]{Slide with Picture in $\frac{2}{3}$ Size}
-% 	\lipsum[1][1-8]
-% \end{frame}
-
-% \begin{frame}[picture 50 vertical,picture=images/palladio_bauplan,kitlogo=black]{Slide with Picture in $\frac{1}{2}$ Size}
-% 	\lipsum[1][1-16]
-% \end{frame}
-
-% \begin{frame}[picture 33 vertical,picture=images/palladio_bauplan,kitlogo=white]{Slide with Picture in $\frac{1}{3}$ Size}
-% 	\begin{columns}
-% 		\column{\kittwocolumns}	
-% 		\lipsum[1][1-8]
-% 		\column{\kittwocolumns}	
-% 		\lipsum[1][1-8]
-% 	\end{columns}
-% \end{frame}
-
-% \begin{frame}[picture vertical=20,picture=images/palladio_bauplan,kitlogo=white]{Slide with Picture in Variable Size (20\%)}
-% 	\lipsum[1][1-16]\footnote{This is a footnote on a page without the navigation bar.}
-% \end{frame}
-
 \subsection{Title and Footer}
 \begin{frame}
         % Bei Frames ohne Titel wird die Kopfzeile nicht angezeigt, und  
@@ -273,9 +272,22 @@
     Citing literature: \cite{klare2021jss}
 \end{frame}
 
-\section{Mode Options}
+\section{Citations}
+\begin{frame}{Citations}
+  Citations in beamer were often dealed by pasting the full text in the footnote. The biblatex package provides a solution allowing you reuse your .bib file for presentations. Here are several ways of usage:\\[-.5em]
+  \begin{itemize}
+  \item cite full text in footnote \footfullcite{art} %or \footnote{\footnotesize\fullcite{art}}
+  \item short citation with author and year in text \autocite{art}
+  \item cite title in text \citetitle{art2}
+  \item \textit{*For more usage please refer to \href{http://tug.ctan.org/info/biblatex-cheatsheet/biblatex-cheatsheet.pdf}{\textcolor{kit-blue}{Biblatex Cheat Sheet}}.}\\
+  \end{itemize}
+  \vspace{-1em}
+  Note that you need to run ``\textbf{Biber}'' instead of ``BibTeX'' to generate the .bbl file.\\
+  You can print all references that are cited at the end of presentation, as shown in the next slide.
+\end{frame}
+
+
 \subsection{Handout Mode}
-\subsection{Face-to-Face Mode}
 \begin{frame}{Itemize List in Handout Mode}
 	\begin{itemize}
         \only<1|handout:0>{\item One: This will not be shown in the handout mode.}
@@ -307,16 +319,17 @@
 \appendix
 \beginbackup
 
-\begin{frame}{Literatur}
+
+\begin{frame}[allowframebreaks]{References}
 \begin{exampleblock}{Backup Parts}
     % Folien, die nach \texttt{\textbackslash beginbackup} eingefügt werden, zählen nicht in die Gesamtzahl der Folien.
 	Slides that are inserted after \texttt{\textbackslash beginbackup} do not count towards the total number of slides.
 \end{exampleblock}
-
 \printbibliography
 \end{frame}
 
 \begin{frame}{KIT Color Palette}\label{frame:kit-colors}
+
 \newcommand{\csq}{\strut\hskip1.2em}
 \begin{tabular}{rccccccccccccc}
 	& 100 & 90 & 80 & 70 & 60 & 50 & 40 & 30 & 25 & 20 & 15 & 10 & 5\\