The instructions to create and add new bookmarks for each type of source are displayed as a revolving gallery of screenshot images. The slides will advance automatically but you can also use the right and left navigation arrows to manually move between slides. There are also instructions on how to add existing bookmarks to your list.
To add an existing bookmark to your list, or to add a particular item to multiple places in your list, go to the classic edit view and drag-and-drop the required bookmark from the right-hand Most recent bookmarks panel to the left-hand list panel.
Go to the Edit list page of this guide to find more information on opening the edit view and saving your draft.