Each page you add in Visual Site Designer is exported as its own HTML file and stored in the _website folder created by Visual Site Designer. The filename is the Page ID you specified in the New Website and New Page Settings windows. This is important information to remember when creating the navigation for your site with Menu Builder because it allows you to create relative and absolute links. For more information about relative and absolute links, read Absolute vs. Relative Paths/Links.
If you are creating a Home button, link to your website URL (e.g. http://www.yourwebsite.com/). Any other buttons should link to the Page ID you give the rest of the pages of your site. For example, let's say we're using one of the built-in templates. Most of them have a Contact page. If we wanted to link to this in Menu Builder, we could use one of the following URLs: http://www.yourdomain.com/contact.html or contact.html.
Note: Make sure to spell the Page ID exactly as it is shown in Visual Site Designer, or the server may not recognize the filename and display an error message instead. Also, be sure to include the .html file extension at the end of the URL, or the browser won't know what type of file to display.