Select the Theme Type option from the dropdown menu of page elements.

1. Select the 100% Width Layout option
2. Save your change
3. Changes saved confirmation

This is a registration website in 100% Width Layout -  which is one page with three sections.

The 100% Width Layout divides your website into 3 sections per page.  The sections are:

1. HEADER
2. BODY
3. FOOTER

Each of the 3 page sections contains layers:

1. The Logo - the top layer, is applied ON TOP of the HEADER BACKGROUND IMAGE - there is no logo option for the BODY and FOOTER sections
2. A BACKGROUND IMAGE - the middle layer, can be applied to the HEADER, BODY and FOOTER sections - it can be repeated vertically, horizontally or both vertically and horizontally (see the caveat below regarding email messages)
3. A BACKGROUND COLOR - the bottom layer, can be applied to the HEADER, BODY and FOOTER areas

The Logo is only IN THE HEADER and applied ON TOP of the BACKGROUND IMAGE which, in turn, is always applied ON TOP of the BACKGROUND COLOR. Therefore, the BACKGROUND IMAGE can obscure the BACKGROUND COLOR. The HEADER BACKGROUND IMAGE does not need to fill the header area. It can be tiled vertically, horizontally or both vertically and horizontally.

Regarding email messages: CAVEAT: Tiling background images is not supported by all email readers.  Therefore, you can expect some deprecation of your theme's appearance in some email readers.  Tiled images are dropped from the display. Therefore, your workaround is to NOT use tiled images.

Select any page element from the dropdown menu. The tool panel will refresh and display the settings that can be changed for that element.

Below is the entire list of page elements for the 100% Width Layout only.  

Page elements for the Fixed Width Layout are in this article: How do I use the Fixed Width editor?