To use graphics in LaTeX, you must include the graphicx package using the declaration below. You should put it in the preamble, after the \documentclass declaration: \usepackage{graphicx}
If you need a graphic or tabular material to be part of the text, you can just put \includegraphics{subdivision} where you want the figure to go. It will not have a caption or any fancy formatting.
If you need it to appear in the list of figures or tables, it should be placed in a float environment (such as figure).
\begin{figure}[htbp]
\begin{centering}
\caption[optional figure title]{figure title. Also more of the caption.}
\includegraphics{subdivision} Do not name the file's extension (.jpg, .pdf), and make sure the file name does not have any spaces.
\label{subd}
\end{centering}
\end{figure}