The default arrangement has the ideal number of sections required for a professional resume. You cannot add extra sections. However, if you’d like to customize the title of the section, it is possible! Just click on a section heading and the field should become editable, allowing you to input your preferred heading. For example - You can change the heading from "Hobbies & Interests" to "Accomplishments or Awards".
If you’d like to delete a section altogether, just delete any information that is in that section. When you preview your resume, you’ll see that that section will not longer appear on your resume.