If fields are the building blocks of the form, then consider the sections (or the left menu) the structure of the registration form.
Anything between and including HEADER and FOOTER are visible sections on the form.
1. Click on the Section you wish to edit from the left menu.
2. Click "Properties" (the link beside the section name at the top) to reveal a table that will allow you to edit the section name, show/hide the subtotal box, change the background color, make the section visible/invisible, and/or delete the section. (as shown below).
3. Click Edit in the second to last column and make the changes you want. Then click Update once your changes are completed.