BigCommerce web pages can contain standard content, use Page Builder where supported, link to another address, or use custom HTML. The available editing tools depend on your store setup.
Use the current BigCommerce web-page guide for the supported page types and navigation settings. Confirm how your theme displays page links before changing the live menu.
If your page needs a custom layout or functionality, send Damien the requirements so the work can be scoped. The video below is an earlier walkthrough; its interface may differ from your current control panel.