\documentclass[../HWThesis.tex]{subfiles}
\begin{document}

\chapter{Design}
\label{ch:design}

Write..
\section{Section}

According to \cite{ghc-pps} ...


\begin{figure}[H]
 \begin{center}
 \includegraphics [width=12cm]{Design/pic.png}
 \caption{Figure Caption.}
 \label{fig:label}
\end{center}
\end{figure} 


\subsection{Subsection}

\begin{table}[H]
\begin{center}
\begin{tabular}{c rrrrrrr} % creating eight columns
\hline\hline %inserting double-line
Audio Name&\multicolumn{7}{c}{Sum of Extracted Bits} \\ [0.5ex] 
\hline % inserts single-line
Police & 5 & -1 & 5& 5& -7& -5& 3\\ % Entering row contents
Midnight & 7 & -3 & 5& 3& -1& -3& 5\\
News & 9 & -3 & 7& 9& -5& -1& 9\\[1ex] % [1ex] adds vertical space
\hline % inserts single-line
\end{tabular}
\caption{Table Caption}
\label{tab:lable}
\end{center}
\end{table}


\subsubsection{Subsubsection}

\end{document}