1. Hover over the header and click Edit section.
2. Add the navigation links you want to include in the drop-down menu.
3. Using the grip icon ⠿, drag and drop each navigation link so it's below the navigation link you want it to drop down from.
To check your navigation links are working, click Preview to test them out. If they're working, click Publish.
Tip: For the navigation link you want the other links to drop down from, set the Link type to Nowhere so it can't be clicked.