You can create a fixed header/floating navigation that remains at the top of your page, even as you scroll down the page. Note that you can only select this option for the first sections on your page.
In order to do this, click on the drop-down menu on the top right corner of your section and select 'Section properties'. This will then give you the option of three types of section types. Click the ‘Fixed Header’ box and ‘Apply’ to confirm changes.
You can choose to have your header floating or standard. Floating navigation is often used if you want your header to float over an image. In this case, you will need to make the background of your header transparent.
See examples below.
*Note that this will only display in published view