It looks like you want a
twosided document. In the MWE I have used
geometry package to set up the page dimensions
caption package to provide the
captionof command, used in the margin figures
changepage package to give the extra width environment that you wanted.
I have also loaded the
lipsum package for sample text, and the
graphicx package to include images.
\usepackage[left=7cm,right=1cm,showframe=true, % page settings (showframe is useful!)
Note that you'll want to remove
showframe=true from the
geometry load, and
[demo] from the
graphicx load- these were just for demonstration.