You can choose from three different types of navbar for your website. The default navbar, transparent navbar and the offscreen navbar.
Once you are in admin dashboard go to website builder and on side bar Click on More button.
Move to the Navbar section and Click on the drop-down list and select the desired Navbar such as Default Navbar, Transparant Navbar, Offscreen Navbar.
You can customize your Navbar by selecting any of those options.
Once the customized Navbar is added then "All navbar links will be cleared and Save changes to your landing page.