A family of Microsoft word processing software products for creating web, email, and print documents.
Display the Styles pane. In the bottom right corner, click Options... In the Style Pane Options dialog, check the box for "Show next heading when previous level is used." Click OK. Now apply Heading 2 to some text. This should cause Heading 3 to appear in the Styles pane. Right-click on it and click Add to Style Gallery.