The main structure of pages in ClickFunnels is divided into four main parts: Sections > Rows > Columns > Elements. This is exactly how professional landing pages are arranged when they're coded from the ground up. Luckily though, you don't have to do that part with ClickFunnels. The structure is already built for you. You just point, click, add, edit, and launch.
These are the main holding containers for the various parts of your pages. You can have 1 section, or many. Rows/Columns/Elements live inside of sections. Sections cannot live inside of a row or a column, rather, they are the bucket for rows and columns to live inside of.
Rows / Columns
The next level is the rows and columns. Rows live inside of sections, and then columns live inside of those rows. You can add a 1 column row, a 2 column row, a 3 column row, and so on.
This is the inner most child of the page structure. The above structure is the layout, and the elements are what make the page interactive. Elements live inside of columns.
This diagram shows how things are stacked inside of the browser, and in the Editor...