Soo Ja Kim,

This is a lot of headings, 5 before text. You can follow a cell-5 heading with a cell-5 heading but you cannot follow a cell-7 heading with a cell-7 heading so I suggest the following. Make sure that you stay consistent with this same hierarchy throughout the book.

6 General (Centered Heading)

6.1 General Settings (Centered Heading)

6.1.1 Language (Cell-5 Heading)

6.1.1.1 Download (Cell-5 Heading)

6.1.1.1.1 Change (Cell 7 Heading)

Text

6.1.1.1.2 Change (Cell 7 Heading)

Text

6.1.1.1.3 Swap voices (Cell 7 Heading)

Text

Great job! Keep up the good work,

Connie