The navigation bar is how users get around a website, and it helps them find important resources quickly. The new Google Sites automatically creates an intuitive navigation bar that links to content within your site, but there may be times when you want to create your own links that go somewhere else. That’s why we’re adding a new feature where you can link to any URL from the navigation bar. You can use this new custom link creator to add an item in the navigation bar that goes to:
Your company’s social media profile or homepage.
Your company’s HCM tool.
Another Google Site with different access permissions.
Your team’s project tracker.
Your team’s Drive folder.
Any other website.
Use Google's Help Centre to find out how to add a custom link in the new Google Sites