How to add a navigation menu

Add a navigation menu into header section:

Put header section in "Edit" mode (button with "Pencil" icon)
Click on the section Add icon ("+")
Choose "Navigation Menu"

Customize navigation "Brand":

The "Brand item" is the left most item in the menu. You can also optionally choose to add a logo image as your navigation brand icon.
Right click on "Brand" and choose "Edit"
Update label to website title
Update link to "index.html"

Update links so all pages are linked to the menu:

Right click on each navigation menu item
Update item label and item link
Delete any extra menu items we do not need

For this example, we want to change the background color from solid white to semi-transparent.
Update navigation menu color and hover selection color:

Menu Settings > Background Color
Drag on transparency slider
Update Hover background color