Your Subpage Fullwidth template allows up to 6 content sections.  Each section can contain text, images, etc.

Content > Sections

Content - This is the main content block and supports the content/styles of the page content.

Background Color - This color allows you to set the background color of the section and should be a html hex value.  A good reference is http://www.w3schools.com/tags/ref_colorpicker.asp.

Background Image - This serves as the section background image.  This image should be 1,280px in width by the desired height (for retina images you can use 2,560px in width).  The height will depend on the amount of content in the section.  A recommended height would be between 600px and 1,200px (double for retina).

Dark Background - Selecting this checkbox displays the content in white color on top of the site default section background color or dark background image.  

Hightlight Color - This allows you to set the highlight color for headings and buttons on certain sections.

Parallax Background - This option turns the Background Image into a parallax background.