**Edited for clarity: **
I am working on a larger document that is primarily written in Word, but I have one chapter that uses Rmarkdown/LaTex. I want to use LaTex features to transform the following LaTex code, using this LaTex image:
\documentclass{article}
\usepackage[utf8]{inputenc}
\title{Sections and Numbering}
\author{Paul Hargarten}
\date{June 2020}
\usepackage{natbib}
\usepackage{graphicx}
\begin{document}
\maketitle
\section{Introduction}
This is the first section.
Lorem ipsum dolor sit amet, consectetuer adipiscing
elit. Etiam lobortisfacilisis sem. Nullam nec mi et
neque pharetra sollicitudin. Praesent imperdietmi nec ante.
Donec ullamcorper, felis non sodales...
\begin{figure}[h!]
\centering
\includegraphics[scale=0.5]{LaTex.png}
\caption{LaTex Text Editor}
\label{fig:LaTex}
\end{figure}
\section{Second Section}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
Etiam lobortis facilisissem. Nullam nec mi et neque pharetra
sollicitudin. Praesent imperdiet mi necante...(Figure \ref{fig:LaTex}).
\end{document}
The code yields this output.
I want to add "Chapter 3" and the corresponding section and figure headers manually. There's no overall title; the document can be considered a chapter from a book. I adjusted the title manually via \title{Chapter 3: Sections and Chapters} . I would like to manually add "3." or tell LaTex to add "3." to the section headers and figures, so the output would read "3.1 Introduction, 3.2 Section 2, etc." as follows.
Chapter 3: Sections and Chapters
3.1 Introduction
This is the first section.
3.2 Second Section
Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
Etiam lobortis facilisissem. Nullam nec mi et neque pharetra
sollicitudin. Praesent imperdiet mi necante... (Figure 3.1).
Figure 3.1: LaTex Text Editor.
Thanks.
