InDesign paper layout

Hey there!
I'd like to make a layout with two columns, one for text and the other for imagens and footnotes related to the text in the first column.
The layout is a A4 paper sheet on landscape. The margins are 2cm top and bottom, 3cm left and 2cm right (mirrored margins). The left column will have 15cm and will accomodate the text and the left column will have 8,7cm and will accomodate images and footnotes. The distance between columns is 1cm.
I imagine it's pretty easy but I'm really newbie on InDesign and need this ASAP for my dissertation.
Thank you very much!

Thanks for your quick reply Matt!
I'm finishing my dissertation and decided to use the InDesign but I never used before :)
And you're right: I know what I want but don't know how to do it!
I'm attaching a sketch I made of the layout I need.
Maybe it will be easier this way ;)
Thanks again!

P.S.: The left side of the page is the inside side of the binder