Click the gear icon in the upper-right corner of the top navigation band.
Navigate to Customization > Layouts and Fields > Tasks.
Click a layout to add a section.
Drag and drop the Add New Section component from the left tray to the layout editor (main panel). Initially the sections will be named “Untitled Section”, “Untitled Section 1”, “Untitled Section 2” and so on as you keep adding new sections in the layout editor.
Hover over the section name and edit it.
You can also add new or existing custom fields to your section.