Add a Link
Open the folder to which you want to add the link by selecting it from the left hand file tree. Because this link will end up in the website navigation, the folder you select must be in the www folder. If you want to add something off the main root of the website, select the www folder itself. This will give you the option to have the link yourdomain.com/link. Hover over the Add button and select the Link button from the dropdown menu.
Fill out the fields in the modal and click the Submit button in the bottom right when complete.