Layout

Hi, I’m having a little trouble with the layout (https://whooplon.com). I’ve got #container, #main, #primary, and it’s getting confusing which should be in the foreground. I want to have the blue background with the post in its current location, and a sidebar to the right (not flush with the right, but floating). Should the #main stretch across the entire page (behind the post, on top of #container), and then add a sidebar??? I’m confused. Thanks for any help!!