Advanced Structure
Use the advanced menu on the right hand side and click on "Manage Structure" this should show you some code. This code represents the structure of your site in terms of the layout and size allocated in the widths and heights within that layout.
Let's start with a basic function of the layout. If you search for CABody in the code window, it should show you something like the in the picture below.

These div tags are the layouts of the site we have. These div tags have a style attached specifically to that div and is advisable to only change them here, so as to save confusion in where you're changing these styles.
You'll notice the divs have specified widths and all float left, so as to stay in the body of the site "CABody", which itself can also be changed if you wish.
Changing these values will affect how your site is going to look and as you can imagine, can drastically change the look of your site.
Any requests for style changes we can perform for you given we have specifics of what it is you would like done.