Under the Menu you would select "sections".
Add: You can add a section from that screen by clicking on the add section button. You can choose which place in order you would like the section to hold (it will default to the bottom), a section name and optional description, as well as an optional image icon for the section.
Delete: You can delete a section by clicking on the wastebasket icon to the right of the section name. (You cannot delete a section that still contains TWILs. The TWILs must be moved or deleted first)
Manage: You have the ability to Edit a section by clicking on the pencil to the right of the section name. You can also change the order of the sections by clicking on the arrows to the left of the section image to move a section up or down on the display.