You can assign different paragraph styles to change the formatting of index titles, separators and index entries. You can also modify paragraph styles in this dialog.
Select the index level that you change the formatting of.
Select the paragraph style that you want to apply to the selected index level, and then click the Assign (<) button.
Formats the selected index level with the selected paragraph style.
Resets the formatting of the selected level to the "Default" paragraph style.
Opens the Paragraph Style dialog, where you can modify the selected paragraph style.