There are 4 out of the 10 available autonav templates at this time that have drop down functionality. They are

Shop Nav (unlimited level)
Shop Header nav (clickable top level link) (unlimited level)
Basic Pills
Basic Tabs

To display the drops, as an example set the auto-nav settings to these exact settings.

Sub Pages to display = Display all
Sub-Page Levels = Display a custom ammount
Levels = 1