how to add and format text & images within page content

I want to create a two column style text layout with images.
so far I am just typing the html into the content area in page editor.
I am trying to just create two divs that float to the left and the right and add the CSS to the custom CSS form built into the theme.

the formatting isnt coming out at all the way im hoping and i not sure if im just doing the html/css wrong or if this method is just wrong.

Thanks